criyle/codenet-compile-errors huggingface dataset:
Language: C++

#include <iostream>
#include <vector>
#define rep(i, n) for (int i = 0; i < (int)(n); i++)
using namespace std;
using ll = long long;
using P = pair<int, int>;

const int MOD = 1E9 + 9;
const ll INF = ll(1e18) + 1;

int main() {
  int n;
  ll k;
  cin >> n >> k;
  vector<long long> a(n);
  rep(i, n) cin >> a[i];
  sort(a.begin(), a.end());
  ll l = -INF, r = INF;
  while (l + 1 < r) {
    ll x = (l + r) / 2;
    bool ok = [&] {
      ll tot = 0;
      rep(i, n) {
        if (a[i] < 0) {
          int l = -1, r = n;
          while (l + 1 < r) {
            int c = (1 + r) / 2;
            if (a[c] * a[i] < x)
              r = c;
            else
              l = c;
          }
          tot += n - r;
        } else {
          int l = -1, r = n;
          while (l + 1 < r) {
            int c = (l + r) / 2;
            if (a[c] * a[i] < x)
              l = c;
            else
              r = c;
          }
          tot += r;
        }
        if (a[i] * a[i] < x) tot--;
      }
      tot /= 2;
      return tot < k;
    }();
    if (ok)
      l = x;
    else
      r = x;
  }
  cout << l << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:17:3: error: 'sort' was not declared in this scope; did you mean 'short'?
   17 |   sort(a.begin(), a.end());
      |   ^~~~
      |   short
Language: C++

#include<cstdio>
#include<algorithm>
#include<cmath>
using namespace std;
typedef long long ll;
ll n,k,a[200002],l=(ll)-1e18-7,r=(ll)1e18+7,mid;
ll rank(ll x) {
	ll s=0,t=0;
	for(ll i=0; i<n; i++) {
		if(a[i]==0)	{
			if(x>=0) t=n-i-1;
			else t=0;
		} else {
			if(x==0) {
				if(a[i]>0) t=0;
				else t=n-i-(lower_bound(a+i+1,a+n,0)-a-i);
			}
			if(x>0) {
				if(a[i]>0) t=upper_bound(a+i+1,a+n,x/a[i])-a-i-1;
				else t=n-(lower_bound(a+i+1,a+n,x/a[i])-a);
			}
			if(x<0) {
				if(a[i]>0) t=0;
				else t=n-(lower_bound(a+i+1,a+n,ceil((double)x/a[i]))-a);
			}
		}


		//printf("%lld %lld %lld\n",upper_bound(a+i+1,a+n,ceil((double)x/a[i]))-a-i-2,t,a[i]);
		if(t>0)	s+=t;



		//printf("%lld %lld %lld %lld\n",x,a[i],t,s);

	}
	return s;
}
int main() {
	//freopen("out.txt","w",stdout);
	scanf("%lld%lld",&n,&k);
	for(ll i=0; i<n; i++) scanf("%lld",&a[i]);
	sort(a,a+n);
	//printf("%lld\n%lld\n%lld\n%lld\n",rank(-12),rank(-10),rank(0),rank(8));
	//printf("%lld \n",rank(6));
	//exit(0);
	while(l<r-1) {
		mid=(l+r)/2;
		//printf("%lld\n",mid);
		if(rank(mid)<k) l=mid;
		else r=mid;
	}
	if(rank(l)<k) printf("%lld",r);
	else printf("%lld",l);
	return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:50:20: error: reference to 'rank' is ambiguous
   50 |                 if(rank(mid)<k) l=mid;
      |                    ^~~~
In file included from /usr/include/c++/14/bits/stl_pair.h:60,
                 from /usr/include/c++/14/bits/stl_algobase.h:64,
                 from /usr/include/c++/14/algorithm:60,
                 from a.cc:2:
/usr/include/c++/14/type_traits:1437:12: note: candidates are: 'template<class> struct std::rank'
 1437 |     struct rank
      |            ^~~~
a.cc:7:4: note:                 'll rank(ll)'
    7 | ll rank(ll x) {
      |    ^~~~
a.cc:53:12: error: reference to 'rank' is ambiguous
   53 |         if(rank(l)<k) printf("%lld",r);
      |            ^~~~
/usr/include/c++/14/type_traits:1437:12: note: candidates are: 'template<class> struct std::rank'
 1437 |     struct rank
      |            ^~~~
a.cc:7:4: note:                 'll rank(ll)'
    7 | ll rank(ll x) {
      |    ^~~~
Language: C++

#include<bits/stdc++.h>
using namespace std;
int main()
{
   long long int a[100000],k;
   int n,i,j;
   int *b=(int*)malloc(sizeof(int)*1000000000000000000);
   cin>>n>>k;
   for(int i=0;i<n;i++){
   	cin>>a[i];
   }
   int q=0;
   for(i=0;i<n;i++){
   	for(j=i+1;j<n;j++){
   		b[q]=a[i]*a[j];
   		q++;
	   }
   }
   sort(b,b+n(n-1)/2);
   cout<<b[k-1]<<endl;
   return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:19:14: error: 'n' cannot be used as a function
   19 |    sort(b,b+n(n-1)/2);
      |             ~^~~~~
Language: C++

#include <bits/stdc++.h>
#define rep(i,n) for(int i=0;i<(n);++i)
using namespace std;
using ll = long long;

const ll INF = ll(1e18)+1;

int msin(void){
    int n; ll k;
    cin >> n >> k;
    vector<ll> a(n);
    rep(i,n) cin >> a[i];
    sort(a.begin(),a.end());
    ll l = -INF,r = INF;
    //二分探索
    while(l+1<r){
        ll x = (l+r)/2;
        bool ok = [&]{
            ll tot = 0;
            rep(i,n){
                if (a[i]<0){
                    int l = -1,r = n;
                    while(l+1<r){
                        int c = (l+r)/2;
                        if(a[c]*a[i] < x) r=c; else l=c;
                    }
                    tot += n-r;
                }else{
                    int l = -1,r = n;
                    while(l+1<r){
                        int c = (l+r)/2;
                        if(a[c]*a[i] < x) l=c; else r=c;
                    }
                    tot += r;
                }
                if (a[i]*a[i] < x) tot --;
            }
            tot /= 2;
            return tot < k;
        }();
        if(ok) l=x;else r=x;
    }
    cout << l << endl;
    return 0;
}

Compiler output:
/usr/bin/ld: /usr/lib/gcc/x86_64-linux-gnu/14/../../../x86_64-linux-gnu/Scrt1.o: in function `_start':
(.text+0x17): undefined reference to `main'
collect2: error: ld returned 1 exit status
Language: C++

#include <bits/stdc++.h>

#define rep(i,n) for (int i = 0; i < (n); ++i)
using namespace std;
typedef long long ll;
using p = pair<int, int>;

const ll INF = ll(1e18)+1;


    int main(){
        int n, ll k;
        std::cin >> n >> k;
        std::vector<int> a(n);
        rep(i, n) std::cin >> a[i];
        sort(a.begin(), a.end());
        ll l = -INF, r = INF;
        while(l+1 < r){
            ll x = (1+r)/2;
            bool ok = [&]{
                ll tot = 0;
                rep(i, n){
                    if(a[i] < 0){
                        int l = -1, r = n;
                        while (l+1<r)
                        {
                            int c = (l+r)/2;
                            if(a[c]*a[i] < x) r = c; else l = c;
                        }
                        tot += n -r;
                    }else{
                        int l = -1, r = n;
                        while (l+1<r)
                        {
                            int c = (l+r)/2;
                            if(a[c]*a[i] < x) l = c; else r = c;
                        }
                        tot += r;
                    }
                    if (a[i]* a[i] < x) tot--;
                }
                tot /= 2;
                return tot < k;
            }();
            if (ok) l = x; else r = x;
        }
        std::cout << l << "\n";
        return 0;
    }
    


Compiler output:
a.cc: In function 'int main()':
a.cc:12:19: error: expected initializer before 'k'
   12 |         int n, ll k;
      |                   ^
a.cc:13:26: error: 'k' was not declared in this scope
   13 |         std::cin >> n >> k;
      |                          ^
Language: C++

#include<iostream>
#include<vector>
#include<string>
#include<queue>
#include<utility>
#include<algorithm>
#include<functional>
#include<map>

using namespace std;

typedef long long int llint;

int N;
llint K;
vector<llint> A;
int pl = 0, mi = 0;//０以上の数、負の値の数

//x未満になるfirstの相方の数(firstが負の数)
llint mC(llint x, int first, int left, int right) {
	//cout << x << "未満となる" << first << "の相方数はmC" << left << "-" << right << endl;
	const int start = left;
	if (A[first] * A[right] >= x) { return 0; }
	if (A[first] * A[left] < x) { return right - left + 1; }
	int middle = (left + right) / 2;
	while (left < right - 1) {
		//cout << "middle = " << middle << endl;
		if (A[first] * A[middle] < x) {
			right = middle;
		}
		else {
			left = middle;
		}
		middle = (left + right) / 2;
	}
	return (llint)(right - start + 1);
}

//x未満になるfirstの相方の数(firstが正の数)
llint pC(llint x, int first, int left, int right) {
	//cout << x << "未満となる" << first << "の相方数はpC" << left << "-" << right << endl;
	const int start = left;
	if (A[first] * A[left] >= x) { return 0; }
	if (A[first] * A[right] < x) { return right - left + 1; }
	int middle = (left + right) / 2;
	while (left < right - 1) {
		//cout << "middle = " << middle << endl;
		if (A[first] * A[middle] < x) {
			left = middle;
		}
		else {
			right = middle;
		}
		middle = (left + right) / 2;
	}
	return (llint)(right - start + 1);
}

//x未満になるペアの総数
llint C(llint x) {
	//llint left, right;
	llint ans = 0;
	for (int i = 0; i < mi; i++) {
		ans += mC(x, i, mi, N - 1);
	}
	for (int i = 0; i < mi - 1; i++) {
		ans += mC(x, i, i + 1, mi - 1);
	}
	for (int i = mi; i < N - 1; i++) {
		ans += pC(x, i, i + 1, N - 1);
	}
	//cout << x << "未満となるペア数:" << ans << endl;
	return ans;
}

int main() {
	cin >> N >> K;
	for (llint i = 0; i < N; i++) {
		llint a;
		cin >> a;
		if (a > 0) { pl++; }
		else { mi++; }
		A.push_back(a);
	}
	sort(A.begin(), A.end());
	//for (int i = 0; i < N; i++) {
	//	cout << "A[" << i << "] = " << A[i] << endl;
	//}

	llint ans = LLONG_MIN;
	//llint left = LLONG_MIN, right = LLONG_MAX, middle = 0;
	llint left = -13, right = 13, middle = 0;
	while (left < right - 1) {
		if (C(middle) < K) {
			ans = max(ans, middle);
			left = middle;
		}
		else {
			right = middle;
		}
		middle = (left + right) / 2;
	}

	cout << ans << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:90:21: error: 'LLONG_MIN' was not declared in this scope
   90 |         llint ans = LLONG_MIN;
      |                     ^~~~~~~~~
a.cc:9:1: note: 'LLONG_MIN' is defined in header '<climits>'; this is probably fixable by adding '#include <climits>'
    8 | #include<map>
  +++ |+#include <climits>
    9 |
Language: C++

N,K=gets.split.map(&:to_i)
A=gets.split.map(&:to_i).sort
L=-(10**30),R=10**30

while(L+1<R)
  MID=(L+R)/2
  SUM=0
  A.each do |i|
    if(A[i]<0)
      SUM+=N-A.bsearch{|x|MID>A[i]*A[x]}
    else
      SUM+=A.bsearch{|x|MID>A[i]*A[x]}
    end
    SUM-=1 if A[i]**2<MID
  end
  SUM/=2
  if SUM<K
    L=MID
  else
    R=MID
  end
end

puts L

Compiler output:
a.cc:1:1: error: 'N' does not name a type
    1 | N,K=gets.split.map(&:to_i)
      | ^
a.cc:11:5: error: expected unqualified-id before 'else'
   11 |     else
      |     ^~~~
a.cc:13:5: error: 'end' does not name a type
   13 |     end
      |     ^~~
Language: C++

#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn = 200005;
typedef long long ll;
ll a[maxn]={0};
int n;
ll find1(ll m){
    ll ret=0;
    ll num=0;
    long double f = 1.0;
    for(int i=0;i<n;i++){
        if(a[i]<0){// m>a[i]*a[j]
                   // a[j]>=m/a[i];
            num=lower_bound(a,a+n,f*m/a[i])-a;
            num=n-num;
        }
        else if(a[i]==0){
            if(m>=0)
                num=n;
            else
                num=0;
        }
        else{
                //m>=a[i]*a[j]
                //a[j]=<m/a[i]
            num=upper_bound(a,a+n,f*m/a[i])-a;
        }
        ret+=num;
        if(a[i]*a[i]<=m)
            ret--;
        //cout << num << endl;
    }
    //cout << ret/2 << endl;
    return ret/2;
}
ll find2(ll m){
    ll ret=0;
    ll num=0;
    long double f = 1.0;
    for(int i=0;i<n;i++){
        if(a[i]<0){// m<=a[i]*a[j]
                   // a[j]<=m/a[i];
            num=upper_bound(a,a+n,f*m/a[i])-a;
        }
        else if(a[i]==0){
            if(m<=0)
                num=n;
            else
                num=0;
        }
        else{
                //m=<a[i]*a[j]
                //a[j]>=m/a[i]
            num=lower_bound(a,a+n,f*m/a[i])-a;
            num=n-num;
        }
        ret+=num;
        if(a[i]*a[i]>=m)
            ret--;
    }
    return ret/2;
}
unordered_map<ll,int>mm;
int check(ll ans){
    for(int i=0;i<n;i++){
        if(a[i]!=0&&ans%a[i]==0){
                if(mm[ans/a[i]])
            return 1;
        }
    }
    return 0;
}
//void pp(ll a){
//    cout << find1(a)<<endl;
//    cout << find2(a)<<endl;
//}
int main()
{
    ll k;
    cin >> n >> k;
    for(int i=0;i<n;i++){
        cin >>a[i];
        mm[a[i]]++;
    }
    sort(a,a+n);
    ll l = -1e18,r=1e18;
    ll m = (l+r)/2;
    ll ans = 0 ;
    find1(0);
    ll ans1,ans2;
    while(l<r){
        ans1=find1(m);
        ans2=find2(m);
        //cout << ans1 << " " << ans2 << endl;
        //cout << l << " " << r <<endl;
        if(ans1>=k&&ans2>=(1ll*n*(n-1)/2-k+1)){
            ans = m ;
            break;
        }
        else if(ans1>=k){
            r=m+1;
        }
        else
            l=m;
        m=(l+r)/2;
        //cout << l <<  " " << r << endl;
    }
    cout << ans << endl;
    //pp(ans);
    //cout <<dd[k-1]<<" "<<dd[k]<<" "<<dd[k+1]<<endl;
    //cout << l << endl;
    //cout << r <<endl;
    return 0;
}


Compiler output:
a.cc:65:1: error: 'unordered_map' does not name a type
   65 | unordered_map<ll,int>mm;
      | ^~~~~~~~~~~~~
a.cc: In function 'int check(ll)':
a.cc:69:20: error: 'mm' was not declared in this scope; did you mean 'tm'?
   69 |                 if(mm[ans/a[i]])
      |                    ^~
      |                    tm
a.cc: In function 'int main()':
a.cc:85:9: error: 'mm' was not declared in this scope; did you mean 'tm'?
   85 |         mm[a[i]]++;
      |         ^~
      |         tm
Language: C++

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <vector>
#include <map>
#include <list>
#include <math.h>
#include <algorithm>
#include <chrono>
#include <random>
#include <queue>
#include <fstream>
#include <iterator> // std::back_inserter
#include <chrono>
#include <string>
#include <stdio.h>
#include <iomanip>
#include <float.h>
#include <cassert>
#include <functional>

using namespace std;

int main(int argc, char *argv[])
{
    int N, K;

    cin >> N >> K;

    vector<long long> a;

    int b;
    for(int i=0; i<N; i++){
        cin >> b;
        a.push_back(b);
    }

    sort(a.begin(), a.end());

    int kouho[K];
    long long last_num = LLONG_MAX;
    list<long long> lst(K,LLONG_MAX);
    bool insert = false;
    bool end = false;


    for(int i=0; i<N-1; i++){
        //cout << a[i] << endl;
        if(a[i] < 0){
            if(a[i] * a[N-1] >= last_num) end = true;
            else{
                for(int j = N-1; j != i; j--){
                    if(a[i] * a[j] >= last_num) break;
                    //cout << a[i] * a[j] << endl;
                    for(auto itr = lst.begin(); itr != lst.end(); ++itr) {
                        if(a[i] * a[j] < *itr){
                            itr = lst.insert(itr, a[i] * a[j]);
                            ++itr;
                            lst.resize(K);
                            auto kari = lst.end();
                            kari--;
                            last_num = *kari;
                            //cout << *kari << endl; 
                            break;
                        }
                    }
                }
            }
        }else{
            if(a[i]*a[i+1] >= last_num) end = true;
            else{
                for(int j = i+1; j < N; j++){
                    //cout << a[i] * a[j] << endl;
                    if(a[i] * a[j] >= last_num) break;
                    
                    for(auto itr = lst.begin(); itr != lst.end(); ++itr) {
                        if(a[i] * a[j] < *itr){
                            itr = lst.insert(itr, a[i] * a[j]);
                            ++itr;
                            lst.resize(K);
                            auto kari = lst.end();
                            kari--;
                            last_num = *kari;
                            //cout << *kari << endl;
                            break;
                        }
                    }
                }
            }
        }
        if(end) break;
    }

    cout << last_num;
    return 0;
}

Compiler output:
a.cc: In function 'int main(int, char**)':
a.cc:41:26: error: 'LLONG_MAX' was not declared in this scope
   41 |     long long last_num = LLONG_MAX;
      |                          ^~~~~~~~~
a.cc:21:1: note: 'LLONG_MAX' is defined in header '<climits>'; this is probably fixable by adding '#include <climits>'
   20 | #include <functional>
  +++ |+#include <climits>
   21 |
Language: C++

#include<bits/stdc++.h>
using namespace std;
priority_queue<long long,vector<long long>,greater<long long> >q;
t<long long>s;
int main()
{
//	freopen("tower10.in","r",stdin);
	//freopen("tower5.out","w",stdout);
	long long n,i,m,j;
	cin>>n;
	long long a1[n],a2[n];
	for(i=0; i<n; i++)
		scanf("%lld",&a1[i]);
	for(i=0; i<n; i++)
		scanf("%lld",&a2[i]);
	sort(a1,a1+n);
	sort(a2,a2+n);
	for(i=0; i<n; i++)
		for(j=0; j<n; j++)
		{
			m=a1[i]+a2[j];
		//	if(!s.count(m))
			{
		//		s.insert(m);
				q.push(m);
			}
		}
	for(i=0; i<n; i++)
	{
		printf("%lld ",q.top());
		q.pop();
	}
//	fclose(stdin);
//fclose(stdout);
	return 0;
}

Compiler output:
a.cc:4:1: error: 't' does not name a type; did you mean 'tm'?
    4 | t<long long>s;
      | ^
      | tm
Language: C++

#include<bits/stdc++.h>
using namespace std;
#define il inline
#define re register
#define int long long
#define D double
il int read() {
    re int x = 0, f = 1; re char c = getchar();
    while(c < '0' || c > '9') { if(c == '-') f = -1; c = getchar();}
    while(c >= '0' && c <= '9') x = x * 10 + c - 48, c = getchar();
    return x * f;
}
#define rep(i , a , b) for(int i = (a) , i##Limit = (b) ; i <= i##Limit ; ++ i)
#define maxn 200005
int n, m, a[maxn], ans, Mi = -1e18, Ma = 1e18, c1, c2, b[maxn], c[maxn], g, d[maxn], c3;
il int check(int x) {
	int tem = 0;
	if(x >= 0) {
		tem = g * (c1 + c2) + g * (g - 1) / 2 + c1 * c2;
		rep(i, 1, c1) tem += upper_bound(b + i + 1, b + c1 + 1, x / b[i]) - b - i - 1;
		rep(i, 1, c2) tem += upper_bound(c + i + 1, c + c2 + 1, x / c[i]) - c - i - 1;
	}
	else {
		x = -x;
		rep(i, 1, c1) tem += c2 + 1, tem -= lower_bound(c + 1, c + c2 + 1, (int)ceil(1.0 * x / b[i]) - c;
	}
	return tem >= m;
}
signed main() {
	n = read(), m = read();
	rep(i, 1, n) a[i] = read();
	rep(i, 1, n) {
		if(a[i] < 0) b[++ c1] = -a[i];
		else if(a[i] > 0) c[++ c2] = a[i];
		else ++ g;
	}
	sort(b + 1, b + c1 + 1), sort(c + 1, c + c2 + 1);
	while(Mi <= Ma) {
		int mid = (Mi + Ma) >> 1;
		if(check(mid)) ans = mid, Ma = mid - 1;
		else Mi = mid + 1;
	}
	cout << ans;
	return 0;
}

Compiler output:
a.cc: In function 'long long int read()':
a.cc:8:12: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
    8 |     re int x = 0, f = 1; re char c = getchar();
      |            ^
a.cc:8:19: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
    8 |     re int x = 0, f = 1; re char c = getchar();
      |                   ^
a.cc:8:34: warning: ISO C++17 does not allow 'register' storage class specifier [-Wregister]
    8 |     re int x = 0, f = 1; re char c = getchar();
      |                                  ^
a.cc: In function 'long long int check(long long int)':
a.cc:25:110: error: invalid operands of types 'long long int' and 'long long int [200005]' to binary 'operator-'
   25 |                 rep(i, 1, c1) tem += c2 + 1, tem -= lower_bound(c + 1, c + c2 + 1, (int)ceil(1.0 * x / b[i]) - c;
      |                                                                                    ~~~~~~~~~~~~~~~~~~~~~~~~~ ^ ~
      |                                                                                    |                           |
      |                                                                                    long long int               long long int [200005]
Language: C++

#include <bits/stdc++.h>//Carefully Crafted by hetp111
using namespace std;
#define int long long
#define double long double
#define all(v) (v).begin(),(v).end()
#define vi vector<int>
#define vvi vector<vi>
#define pii pair<int,int>
#define vii vector<pii>
#define MOD (1000000007)
//#define MOD (998244353)
#define PI acos(-1)
#define eps (1e-8)
#define INF (1e18)
#define FASTER ios_base::sync_with_stdio(0);cin.tie(0)
template<class A,class B>ostream&operator<<(ostream&out,const pair<A,B>&a){return out<<"("<<a.first<<","<<a.second<<")";}
template<class A>ostream&operator<<(ostream&out,const vector<A>&a){for(const A &it:a)out<<it<<" ";return out;}
template<class A,class B>istream&operator>>(istream&in,pair<A,B>&a){return in>>a.first>>a.second;}
template<class A>istream&operator>>(istream&in,vector<A>&a){for(A &i:a)in>>i;return in;}
//ifstream cinn("input.txt");ofstream coutt("output.txt");

int n,k,zero;
vi v;

int nolessthe(int xy){
    int tot=0;
    for(const int &x:v){
        if(xy>0){
            if(x<0){
                
            }else if(x>0){
                
            }
        }else if(xy<0){
            if(x<0){
                
            }else if(x>0){
                
            }
        }else{
            
        }
    }
    return tot/2;
}

signed main(){
    FASTER;
    cin>>n>>k;
    v=vi(n);cin>>v;
    sort(all(v));
    
    int s=-INF,e=INF,ans;
    while(s<=e){
        int mid=(s+e)/2;
        if(nolessthen(mid)>k){
            s=mid-1;
        }else if(nolessthen(mid)<k){
            e=mid+1;
        }else{
            ans=mid;
            break;
        }
    }
    cout<<ans;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:56:12: error: 'nolessthen' was not declared in this scope; did you mean 'nolessthe'?
   56 |         if(nolessthen(mid)>k){
      |            ^~~~~~~~~~
      |            nolessthe
Language: C++

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<ll,ll> pll;

ll inf=ll(1e18)+1;

int main() {
  ll n,k;
  ll zero=0;
  cin >> n >> k;
  vector<ll> a(n);
  ll mnum=0,znum=0;
  for(ll i=0;i<n;i++) {
    cin >> a[i];
    if(a[i]<0) {
      mnum++;
    }
    if(a[i]==0) {
      znum++;
    }
  }
  vector<ll> m(mnum);
  vector<ll> mg(mnum);
  vector<ll> p(n-mnum-znum);
  vector<ll> z(znum,0);
  sort(a.begin(),a.end());
  for(ll i=0;i<n;i++) {
    if(i<mnum) {
      m[i]=-a[i];
      mg[i]=a[i];
    }
    else if(i>=mnum+znum){
      p[i-mnum-znum]=a[i];
    }
  }
  sort(m.begin(),m.end());
  ll ok=-inf,ng=inf;
  ll temp=(ng+ok)/2;
  while(ok+1<ng) {
    ll count=0;
    if(temp<0) {
      for(ll i=0;i<p.size();i++) {
        count+=upper_bound(mg.begin(),mg.end(),(temp-p[i]+1)/p[i])-mg.begin();
      }
    }
    else if(temp==0) {
      count+=m.size()*p.size()
    }
    else {
      count+=m.size()*p.size()*2;
      count+=z.size()*(p.size()+m.size())*2+z.size()*(z.size()-1);
      for(ll i=0;i<p.size();i++) {
        ll id=upper_bound(p.begin(),p.end(),temp/p[i])-p.begin();
        if(id>i) {
          id--;
        }
        count+=id;
      }
      for(ll i=0;i<mg.size();i++) {
        ll id=upper_bound(m.begin(),m.end(),temp/m[i])-m.begin();
        if(id>i) {
          id--;
        }
        count+=id;
      }
      if(count%2) {
        cout << "error" << endl;
      }
      count/=2;
    }
    if(count<k) {
      ok=temp;
    }
    else {
      ng=temp;
    }
    temp=(ok+ng)/2;
  }
  cout << ng << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:48:31: error: expected ';' before '}' token
   48 |       count+=m.size()*p.size()
      |                               ^
      |                               ;
   49 |     }
      |     ~
Language: C++

#include <bits/stdc++.h>
#include <math.h>
#include <algorithm>
#define rep(i, n) for(int i = 0; i < n; ++i)
using namespace std;

int main() {
  int64_t n, k, a, b, c, xm, x0, ans, tmp;
  cin >> n >> k;
  vector<int64_t> v(n);
  rep(i, n) cin >> v[i];
  sort(v.begin(), v.end());
  xm = lower_bound(v.begin(), v.end(), 0) - v.begin();
  x0 = upper_bound(v.begin(), v.end(), 0) - v.begin();
  a = xm*(xm-1)/2;
  c = (n-x0)*(n-x0-1)/2;
  b = n*(n-1)/2 - a - c;
  if(k > a + b){
    tmp = 72057594037927936;
    rep(i, 56){
      int64_t l = 0
      rep(j, n) l += upper_bound(v.begin(), v.end(), tmp/v[j]);
      if(k > l) tmp += pow(2, 55-i);
      else tmp -= pow(2, 55-i);
    }
    rep(j, n) k -= upper_bound(v.begin(), v.end(), tmp/v[j]);
    if(k > 0) ++tmp;
    ans = tmp;
  }
  else if(k > a) ans = 0;
  else{
    tmp = -72057594037927936;
    rep(i, 56){
      int64_t l = 0
      rep(j, n) l += upper_bound(v.begin(), v.end(), tmp/v[j]);
      if(k > l) tmp += pow(2, 55-i);
      else tmp -= pow(2, 55-i);
    }
    rep(j, n) k -= upper_bound(v.begin(), v.end(), tmp/v[j]);
    if(k > 0) ++tmp;
    ans = tmp;
  }
  cout << ans << endl;
  return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:4:19: error: expected ',' or ';' before 'for'
    4 | #define rep(i, n) for(int i = 0; i < n; ++i)
      |                   ^~~
a.cc:22:7: note: in expansion of macro 'rep'
   22 |       rep(j, n) l += upper_bound(v.begin(), v.end(), tmp/v[j]);
      |       ^~~
a.cc:22:11: error: 'j' was not declared in this scope
   22 |       rep(j, n) l += upper_bound(v.begin(), v.end(), tmp/v[j]);
      |           ^
a.cc:4:34: note: in definition of macro 'rep'
    4 | #define rep(i, n) for(int i = 0; i < n; ++i)
      |                                  ^
a.cc:26:17: error: no match for 'operator-=' (operand types are 'int64_t' {aka 'long int'} and '__gnu_cxx::__normal_iterator<long int*, std::vector<long int> >')
   26 |     rep(j, n) k -= upper_bound(v.begin(), v.end(), tmp/v[j]);
      |               ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
a.cc:4:19: error: expected ',' or ';' before 'for'
    4 | #define rep(i, n) for(int i = 0; i < n; ++i)
      |                   ^~~
a.cc:35:7: note: in expansion of macro 'rep'
   35 |       rep(j, n) l += upper_bound(v.begin(), v.end(), tmp/v[j]);
      |       ^~~
a.cc:35:11: error: 'j' was not declared in this scope
   35 |       rep(j, n) l += upper_bound(v.begin(), v.end(), tmp/v[j]);
      |           ^
a.cc:4:34: note: in definition of macro 'rep'
    4 | #define rep(i, n) for(int i = 0; i < n; ++i)
      |                                  ^
a.cc:39:17: error: no match for 'operator-=' (operand types are 'int64_t' {aka 'long int'} and '__gnu_cxx::__normal_iterator<long int*, std::vector<long int> >')
   39 |     rep(j, n) k -= upper_bound(v.begin(), v.end(), tmp/v[j]);
      |               ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Language: C++

#include <iostream>
#include <algorithm>
#include <vector>

using std::cin;
using std::cout;
using std::endl;
using std::sort;
using std::vector;


int main() {
    ushort* n = new ushort;
    ushort* k = new ushort;
    long* tmp = new long;
    cin >> *n >> *k;
    vector<long> num;
    vector<long long int> multiplication;
    for(unsigned short int i = 0; i < *n; i++) {
        cin >> *tmp;
        num.push_back(*tmp);
    }
    for(unsigned short int i = 0; i < *n; i++) {
        for(unsigned short int j = i + 1; j < *n; j++) {
            multiplication.push_back(num[i] * num[j]);
        }
    }
    vector<long>().swap(num);
    sort(multiplication.begin(), multiplication.end());
    cout << multiplication[*k-1] << endl;
    vector<long>().swap(multiplication);
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:31:25: error: cannot convert 'std::vector<long long int>' to 'std::vector<long int>&'
   31 |     vector<long>().swap(multiplication);
      |                         ^~~~~~~~~~~~~~
      |                         |
      |                         std::vector<long long int>
In file included from /usr/include/c++/14/vector:66,
                 from a.cc:3:
/usr/include/c++/14/bits/stl_vector.h:1588:20: note:   initializing argument 1 of 'void std::vector<_Tp, _Alloc>::swap(std::vector<_Tp, _Alloc>&) [with _Tp = long int; _Alloc = std::allocator<long int>]'
 1588 |       swap(vector& __x) _GLIBCXX_NOEXCEPT
      |            ~~~~~~~~^~~
Language: C++

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
#define MOD 1000000007
#define rep(i,m,n) for(int (i)=(int)(m);i<(int)(n);i++)
#define REP(i,n) rep(i,0,n)
#define FOR(i,c) for(decltype((c).begin())i=(c).begin();i!=(c).end();++i)
#define ll long long
#define ull unsigned long long
#define all(hoge) (hoge).begin(),(hoge).end()
const long long INF = 1LL << 60;
typedef vector<ll> Array;

int main() {
	ios::sync_with_stdio(false);
	cin.tie(0);

	ll n, k;
	cin >> n >> k;
	Array a(n);
	REP(i, n)cin >> a[i];
	sort(all(a));
	auto find = [&](ll tar,ll u) {
		ll l = -1, r = n;
		while (r - l > 1) {
			ll mid = (r + l) / 2;
			if (u * a[mid] <= tar) {
				if (u >= 0)l = mid;
				else r = mid;
			}
			else {
				if (u >= 0)r = mid;
				else l = mid;
			}
		}
		if (u >= 0)return l + 1;
		else return n - f;
	};
    ll l = -INF, r = INF;
	while (r - l > 1) {
		ll mid = (r + l) / 2;
		ll cnt = 0;
		REP(i, n) {
			cnt += find(mid, a[i]);
			if (a[i] * a[i] <= mid)cnt--;
		}
		if (cnt / 2 >= k)r = mid;
		else l = mid;
	}
	cout << r << endl;

	return 0;
}

Compiler output:
a.cc: In lambda function:
a.cc:38:33: error: 'f' was not declared in this scope
   38 |                 else return n - f;
      |                                 ^
Language: Java

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.HashSet;
import java.util.List;
import java.util.stream.Stream;

public class Main{
    public static void main(String[] args)throws IOException{
        BufferedReader input = new BufferedReader(new InputStreamReader(System.in));
        String[] nk = input.readLine().split(" "); 
        int n = Integer.parseInt(nk[0]);
        long k = Long.parseLong(nk[1]);
        long count = 0;
        String[] an = input.readLine().split(" ");
        long[] na = Stream.of(an).mapToLong(Long::parseLong).toArray();
        long[] cul = new long[(na.length * (na.length - 1))/2];
        for(int i = 0; i < n-1; i++){
            for(int j = i + 1; j < n ; j++){
                cul[count] = na[i] * na[j];
                count++;
                
            }
        }
        Arrays.parallelSort(cul);
        System.out.println(cul[(int) (k - 1)]);

        }

    }

Compiler output:
Main.java:23: error: incompatible types: possible lossy conversion from long to int
                cul[count] = na[i] * na[j];
                    ^
1 error
Language: C++

#include<bits/stdc++.h>
#include <boost/rational.hpp>
#include <boost/multiprecision/cpp_int.hpp>
#define ll long long
#define ALL(v) (v).begin(),(v).end()
#define REP(i,p,n) for(int i=p;i<(int)(n);++i)
#define rep(i,n) REP(i,0,n)
#define dump(a) (cerr << #a << "=" << (a) << endl)
#define DUMP(list) cout << "{ "; for(auto nth : list){ cout << nth << " "; } cout << "}" << endl;
template<class T> inline bool chmax(T& a, T b) { if (a < b) { a = b; return true; } return false; }
template<class T> inline bool chmin(T& a, T b) { if (a > b) { a = b; return true; } return false; }

const ll INF = ll(1e18) + 1;
using namespace std;

int main(){
    int n; ll k;
    cin >> n >> k;
    vector<ll> a(n);
    rep(i, n) cin >> a[i];
    sort(a.begin(), a.end());
    ll l = -INF, r = INF;
    while (l + 1 < r) {
        ll x = (l + r) / 2;
        bool ok = [&] {
            ll tot = 0;
            rep(i, n) {
                if (a[i] < 0) {
                    int l = -1, r = n;
                    while(l+1<r) {
                        int c = (l+r) / 2;
                        if (a[c]*a[i] < x) r = c; else l = c;
                    }
                    tot += n - r;
                } else {
                    int l = -1, r = n;
                    while (l + 1 < r) {
                        int c = (l + r) / 2;
                        if (a[c]*a[i] < x) l = c; else r = c;
                    }
                    tot += r;
                }
                if (a[i] * a[i] < x) tot--;
            }
            tot /= 2;
            return tot < k;

        }();
        if (ok) l = x; else r = x;

    }
    cout << l << endl;
}

Compiler output:
a.cc:2:10: fatal error: boost/rational.hpp: No such file or directory
    2 | #include <boost/rational.hpp>
      |          ^~~~~~~~~~~~~~~~~~~~
compilation terminated.
Language: C++

#include <bits/stdc++.h>
//#include <boost/multiprecision/cpp_int.hpp>
//#include <ext/pb_ds/assoc_container.hpp>
//#include <ext/pb_ds/tree_policy.hpp>
#pragma GCC optimize("O3")
#define REP(i,n) for(int i=0;i<n;i++)
#define REPP(i,n) for(int i=1;i<=n;i++)
#define ALL(obj) (obj).begin(), (obj).end()
#define EPS (1e-9)
#define INF (1e17)
#define PI (acos(-1))
//const double PI = acos(-1);
//const double EPS = 1e-15;
//long long INF=(long long)1E17;
#define i_7 (long long)(1e9+7)
//#define i_7 998'244'353
long mod(long a){
    long long c=a%i_7;
    if(c>=0)return c;
    return c+i_7;
}
long long po(long a, long b){
    if(b==0){
        return 1;
    }
    
    long long z = po(a,b/2);
    z = mod(z*z);
    if(b%2!=0){
        z = mod(a*z);
    }
    return z;
}

bool prime_(int n){
  if(n==1){
    return false;
  }else if(n==2){
    return true;
  }else{
    for(int i=2;i<=std::sqrt(n);i++){
      if(n%i==0){
        return false;
      }
    }
    return true;
  }
}

long long gcd_(long long a, long long b){
  if(a<b){
    std::swap(a,b);
  }
  if(a%b==0){
    return b;
  }else{
    return gcd_(b,a%b);
  }
}
 
long long lcm_(long long x, long long y){
  return (x/gcd_(x,y))*y;
}

//using namespace std;
//using namespace boost::multiprecision;
//using namespace __gnu_pbds;

int main(){
  using namespace std;
  long long n, k;
  cin>>n>>k;
  vector<long long> a(n);
  REP(i, n){
    cin>>a[i];
  }
  sort(ALL(a));
  long long l = -1e18;
  long long r = long long(1e18) + 1;
  while(r - l > 1){
    long long m = (l + r) / 2;
    long long cnt = 0;
    REP(i, n){
      if(a[i] > 0){
        if(m % a[i] == 0){
          cnt += distance(lower_bound(ALL(a), m/a[i]), a.begin());
        }else{
          if(m >= 0){
            cnt += distance(upper_bound(ALL(a), m/a[i]), a.begin());
          }else{
            cnt += distance(upper_bound(ALL(a), m/a[i] - 1), a.begin());
          }
        }
        if(a[i] * a[i] < m)cnt--;
      }else if(a[i] < 0){
        long long temp;
        if(m % a[i] == 0){
          temp = distance(upper_bound(ALL(a), m/a[i]), a.begin());
        }else{
          if(m <= 0){
            temp = distance(upper_bound(ALL(a), (-m)/(-a[i])), a.begin());
          }else{
            temp = distance(upper_bound(ALL(a), (-m)/(-a[i]) - 1), a.begin());
          }
        }
        cnt += n - temp;
        if(a[i] * a[i] < m)cnt--;
      }else{
        if(0 < m){
          cnt += n - 1;
        }else{
          continue;
        }
      }
    }
    cnt /= 2;
    if(cnt < k){
      l = m;
    }else{
      r = m;
    }
  }
  cout<<l<<endl;
  return 0;
}



Compiler output:
a.cc: In function 'int main()':
a.cc:79:17: error: expected primary-expression before 'long'
   79 |   long long r = long long(1e18) + 1;
      |                 ^~~~
Language: C++

#include <iostream>
#include <vector>
#include <climits>

using namespace std;

using ll = long long;

int count_lts(ll x, ll k, vector<ll> const& v, int start, int last) {
  if (x <= k * v[start]) return 0;
  auto l = start, r = last;
  while (r - l > 1) {
    auto m = (l + r) / 2;
    ((k * v[m] < x) ? l : r) = m;
  }
  return r - start;
}

int count_les(ll x, ll k, vector<ll> const& v, int start, int last) {
  if (x < k * v[start]) return 0;
  auto l = start, r = last;
  while (r - l > 1) {
    auto m = (l + r) / 2;
    ((k * v[m] <= x) ? l : r) = m;
  }
  return r - start;
}

int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  ll n, k;
  cin >> n >> k;
  vector<ll> poss, negs;
  ll zeros = 0;
  for (ll i = 0; i < n; i++) {
    ll a;
    cin >> a;
    if (a > 0)
      poss.push_back(a);
    else if (a == 0)
      zeros++;
    else
      negs.push_back(a);
  }
  sort(begin(poss), end(poss));
  sort(begin(negs), end(negs));
  ll nps = poss.size() * negs.size(),
     nzs = zeros * (poss.size() + negs.size()) + zeros * (zeros - 1) / 2;
  if (k <= nps) {
    ll l = -LLONG_MAX / 2, r = 0;
    while (r - l > 1) {
      ll m = (l + r) / 2;
      int le = 0, lt = 0;
      for_each(rbegin(poss), rend(poss), [&] (auto p) {
        le += count_les(m, p, negs, 0, negs.size());
        lt += count_lts(m, p, negs, 0, negs.size());
      });
      if (lt < k && k <= le) {
        l = m;
        break;
      }
      (le < k ? l : r) = m;
    }
    cout << l << endl;
  }
  else if (k <= nps + nzs) {
    cout << 0 << endl;
  }
  else {
    ll l = 0, r = LLONG_MAX / 2;
    int rest = k - nps - nzs;
    vector<ll> pneg(negs.size());
    for (int i = 0; i < negs.size(); i++)
      pneg[negs.size() - 1 - i] = -negs[i];
    while (r - l > 1) {
      ll m = (l + r) / 2;
      int le = 0, lt = 0;
      for (int i = 0; i < poss.size(); i++) {
        le += count_les(m, poss[i], poss, i + 1, poss.size());
        lt += count_lts(m, poss[i], poss, i + 1, poss.size());
      }
      for (int i = 0; i < pneg.size(); i++) {
        le += count_les(m, pneg[i], pneg, i + 1, pneg.size());
        lt += count_lts(m, pneg[i], pneg, i + 1, pneg.size());
      }
      if (lt < rest && rest <= le) {
        l = m;
        break;
      }
      (le < rest ? l : r) = m;
    }
    cout << l << endl;
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:46:3: error: 'sort' was not declared in this scope; did you mean 'short'?
   46 |   sort(begin(poss), end(poss));
      |   ^~~~
      |   short
a.cc:55:7: error: 'for_each' was not declared in this scope
   55 |       for_each(rbegin(poss), rend(poss), [&] (auto p) {
      |       ^~~~~~~~
Language: C++

#include <bits/stdc++.h>
using namespace std;
using i64 = long long;
#define rep(i,s,e) for(i64 (i) = (s);(i) < (e);(i)++)
#define all(x) x.begin(),x.end()

template<class T>
static inline std::vector<T> ndvec(size_t&& n, T val) noexcept {
  return std::vector<T>(n, std::forward<T>(val));
}

template<class... Tail>
static inline auto ndvec(size_t&& n, Tail&&... tail) noexcept {
  return std::vector<decltype(ndvec(std::forward<Tail>(tail)...))>(n, ndvec(std::forward<Tail>(tail)...));
}



int main() {
  i64 N, K;
  cin >> N >> K;
  vector<i64> A(N);
  long long p=0;
  long long q=0;
  rep(i,0,N){
      cin >> A[i];
      if(a[i]<0){
          p++;
      }
      else{
          q++;
      }
  }
  if(K<=p*q){
      return 0;
  }
  i64 mi = 0;
  i64 ze = 0;
  i64 pl = 0;
  rep(i,0,N) {
    if(A[i] < 0) mi++;
    if(A[i] == 0) ze++;
    if(A[i] > 0) pl++;
  }
  if(K <= mi * pl) {
    i64 ok = 1e18 + 10;
    i64 ng = 0;
    vector<i64> X;
    vector<i64> Y;
    rep(i,0,N) {
      if(A[i] < 0) X.push_back(-A[i]);
      else if(A[i] > 0) Y.push_back(A[i]);
    }
    sort(all(X));
    sort(all(Y));
    while(ok - ng > 1) {
      i64 mid = (ok + ng) / 2;
      i64 j = Y.size();
      i64 ans = 0;
      for(i64 i = 0;i < X.size(); i++) {
        while(j > 0 && Y[j - 1] * X[i] > mid) {
          j--;
        }
        ans += j;
      }
      ans = mi * pl - ans;
      //cout << mid << " = " << ans << endl;
      if(ans < K) ok = mid;
      else ng = mid;
    }
    cout << -ok << endl;
    return 0;
  }
  else if(K <= mi * pl + ze * (mi + pl) + ze * (ze - 1) / 2) {
    cout << 0 << endl;
    return 0;
  }
  else {
    K -= mi * pl + ze * (mi + pl) + ze * (ze - 1) / 2;
    i64 ng = 1e18 + 10;
    i64 ok = 0;
    vector<i64> X;
    vector<i64> Y;
    rep(i,0,N) {
      if(A[i] < 0) X.push_back(-A[i]);
      else if(A[i] > 0) Y.push_back(A[i]);
    }
    sort(all(X));
    sort(all(Y));
    while(ng - ok > 1) {
      i64 mid = (ok + ng) / 2;
      i64 j = X.size();
      i64 ans = 0;
      for(i64 i = 0;i < X.size(); i++) {
        while(j > 0 && X[j - 1] * X[i] > mid) {
          j--;
        }
        if(j <= i) break;
        ans += j - i - 1;
      }
      j = Y.size();
      for(i64 i = 0;i < Y.size(); i++) {
        while(j > 0 && Y[j - 1] * Y[i] > mid) {
          j--;
        }
        if(j <= i) break;
        ans += j - i - 1;
      }
      //cout << mid << " = " << ans << endl;
      if(ans < K) ok = mid;
      else ng = mid;
    }
    cout << ok + 1 << endl;
    return 0;
  }
}


Compiler output:
a.cc: In function 'int main()':
a.cc:27:10: error: 'a' was not declared in this scope
   27 |       if(a[i]<0){
      |          ^
Language: C

#include <stdio.h>
#include <stdlib.h>

int compare_int(const void *a, const void *b)
{
  long *A = (long *)a;
  long *B = (long *)b;
  if (*A > *B) return 1;
  if (*A < *B) return -1;
  return 0;
}


int main() {
  	unsigned int N;
	int* A;  	
  	long* prod;
  	unsigned long K, count=0;
  	scanf("%d %lu", &N, &K);
  	A = (int*)malloc(sizeof(int)*N);
  	for(int i=0; i < N;i++){
    	scanf("%d ", &A[i]);
    }
  	prod = (long*)malloc(sizeof(long)*(unsigned long)(N*(N-1)/2));
  	for(int i=0; i < N; i++){
    	for(int j = i+1;j < N; j++){
        	prod[count] = (long)((long)(A[i]) * (long)(A[j]));
          	//printf("%ld\n", prod[count]);
          	count++;
        }
    }
  	free(A);
  	qsort(prod, (unsigend long)(N*(N-1)/2), sizeof(long), compare_int);
  	printf("%ld", prod[K-1]);
  	free(prod);
	return 0;
}


Compiler output:
main.c: In function 'main':
main.c:33:22: error: 'unsigend' undeclared (first use in this function)
   33 |         qsort(prod, (unsigend long)(N*(N-1)/2), sizeof(long), compare_int);
      |                      ^~~~~~~~
main.c:33:22: note: each undeclared identifier is reported only once for each function it appears in
main.c:33:30: error: expected ')' before 'long'
   33 |         qsort(prod, (unsigend long)(N*(N-1)/2), sizeof(long), compare_int);
      |                     ~        ^~~~~
      |                              )
Language: C++

// agrawal117
//chahatagrawal117
#pragma GCC optimize("O3", "unroll-loops")
#pragma GCC target("avx2")
#include<bits/stdc++.h>
#define endl '\n'
using namespace std;
typedef long long int ll;
#define MAX 1005
vector<ll> v;
ll check(ll n)
{
    ll ans=0;
    for(int i=0;i<v.size();i++){
        if(v[i]==0){
            if(n>=0) ans+=(v.size()-i-1);
            else continue;
        }
        int j;
        if(v[i]<0 && n<=0){
            ll x=abs(n); ll y=abs(v[i]);
            ll val=x/y;
            if(x%y!=0) val++;
            j=lower_bound(v.begin()+i+1,v.end(),val)-v.begin();
            // cout<<j<<endl;
            ans+=(v.size()-j);
            continue;
            
        }
        if(v[i]<0 && n>0) {
            ll x=abs(n); ll y=abs(v[i]);
            ll val=x/y;
            if(x%y!=0) val++;
            val=val*(-1);
            j=lower_bound(v.begin()+i+1,v.end(),val)-v.begin();
            // cout<<j<<endl;
            ans+=v.size()-j;
            continue;
            
        }
        if(v[i]>0 && n<0) {
            ll x=abs(n); ll y=abs(v[i]);
            ll val=x/y;
            if(x%y!=0) val++;
            val*=-1;
            j=upper_bound(v.begin()+i+1,v.end(),val)-v.begin();
            // cout<<j<<endl;
            ans+=(j-i-1);
            continue;
        }
        if(v[i]>0 && n>=0) {
            j=upper_bound(v.begin()+i+1,v.end(),ll(n/v[i]))-v.begin();
            ans+=(j-i-1);
            // cout<<j<<endl;
            continue;
        }
    }
    return ans;
}
int main()
{
   ll n,k;
   cin>>n>>k;
   for(int i=0;i<n;i++) {
       ll a; cin>>a;
       v.push_back(a);
   }
   sort(v.begin(),v.end());
   ll end=1000000000000000000;
   ll start=-1*end;
  while(true){
      ll mid=(start+end)/2;
      ll val= check(mid);
    //   cout<<mid<<" val--> "<<val<<endl;
      if(val<k) start=mid;
      else end=mid;
      if(end-start<=1) break;
  }
//   cout<<start<<" "<<end<<endl;
   ll val= check(start);
//   cout<<val<<endl;
  if(val>=k) {
      cout<<start<<endl;
  }
  val=check(end);
//   cout<<val<<endl;
    if(val>=k)cout<<end<<endl;

Compiler output:
a.cc: In function 'int main()':
a.cc:87:31: error: expected '}' at end of input
   87 |     if(val>=k)cout<<end<<endl;
      |                               ^
a.cc:61:1: note: to match this '{'
   61 | {
      | ^
Language: C++

#include <bits/stdc++.h>
using namespace std;
#define int long long
const long long LINF=1e18;

signed main(){
  int n,k;cin>>n>>k;
  vector<int> v(n);
  for(int i=0;i<n;i++)cin>>v[i];
  sort(v.begin(),v.end());
  int ng=-LINF,ok=LINF;//
  while(ng-ok>1){
    int mid=(ng+ok)>>1;
    int tmp=0;
    for(int i=0;i<n;i++){
      if(v[i]>0){
        int l=-1,r=n;
        while(r-l>1){
          int m=(r+l)>>1;
          if(v[i]*v[m]>mid)r=m;
          else l=m;
        }
        tmp+=r;
        if(v[i]*v[i]<=mid)tmp--;
      }
      if(!v[i])if(mid>=0)tmp+=n-1;
      if(v[i]<0){
        int l=-1,r=n;//rrはmid以下
        while(r-l>1){
          int m=(r+l)>>1;
          if(v[i]*v[m]>mid)l=m;
          else r=m;
        }
        tmp+=n-rr;
        if(v[i]*v[i]<=mid)tmp--;
      }
    }
    if(tmp>=k*2)ok=mid;
    else ng=mid;
  }
  cout<<ok<<endl;
}


Compiler output:
a.cc: In function 'int main()':
a.cc:34:16: error: 'rr' was not declared in this scope; did you mean 'r'?
   34 |         tmp+=n-rr;
      |                ^~
      |                r
Language: C++

#include "stdafx.h"
#include <bits/stdc++.h>
#define f(i,n) for(int i=0;i<n;i++)
#define P pair<int,int>
#define F first
#define S second
#define int long long
using namespace std;
int a, b;
int x[200000];
void mutu() {
	int l = pow(10, 18)*-1 - 1, r = pow(10, 18), y = 0;
	while (r - l > 1) {
		int z = (r + l) / 2;
		cout << z << endl;
		y = 0;
		f(i, a) {
			if (x[i] < 0 && z >= 0) {
				int vz = lower_bound(x, x + a, z / x[i]) - x;
				if (vz <= i) y--;
				y += a - vz;
			}
			if (x[i] < 0 && z < 0) {
				int vz = lower_bound(x, x + a, z / x[i] + 1) - x;
				if (vz <= i)y--;
				y += a - vz;
			}
			if (x[i] == 0 && z >= 0) {
				y += a - 1;
			}
			if (x[i] > 0 && z < 0) {
				int vz = lower_bound(x, x + a, (z + 1) / x[i]) - x;
				if (i < vz)y--;
				y += vz;
			}
			if (x[i] > 0 && z >= 0) {
				int vz = lower_bound(x, x + a, z / x[i] + 1) - x;
				if (i < vz)y--;
				y += vz;
			}
			if (z == 4)cout << y << endl;
		}
		if (y >= b*2)r = z;
		else l = z;
	}
	cout << r << endl;
}
signed main() {
	cin >> a >> b;
	f(i, a) {
		cin >> x[i];
	}
	sort(x, x + a);
	mutu();
}


Compiler output:
a.cc:1:10: fatal error: stdafx.h: No such file or directory
    1 | #include "stdafx.h"
      |          ^~~~~~~~~~
compilation terminated.
Language: C++

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

int main() {
    ll n, k, a[200000], mib, mab, c, b, co, mi, ma, i, mm;
    cin >> n >> k;
    for (i = 0; i < n; i++) {
        cin >> a[i];
    }
    sort(a, a + n);
    mib = -2000000000000000000LL;
    mab = 2000000000000000000LL;
    c = 0;
    while (mib != mab) {
        b = (mab + mib - _abs64(mab + mib) % 2) / 2;
        co = 0;
        for (int j = 0; j < n;j++) {
            i = a[j];
            mi = 0;
            ma = n - 1;
            if (i >= 0) {
                if (i * a[0] > b) {
                    continue;
                }
                while (mi != ma) {
                    mm = (mi + ma) / 2 + 1;
                    if (i * a[mm] <= b) {
                        mi = mm;
                    } else {
                        ma = mm - 1;
                    }
                }
                co += mi + 1;
                if (i * i <= b) {
                    co -= 1;
                }
            } else {
                if (i * a[n - 1] > b) {
                    continue;
                }
                while (mi != ma) {
                    mm = (mi + ma) / 2;
                    if (i * a[mm] <= b) {
                        ma = mm;
                    } else {
                        mi = mm + 1;
                    }
                }
                co += n - mi;
                if (i * i <= b) {
                    co -= 1;
                }
            }
        }
        //cout << co << endl;
        if (co / 2 >= k) {
            mab = b;
        } else {
            mib = b + 1;
        }

    }
    cout << mib << endl;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:16:26: error: '_abs64' was not declared in this scope; did you mean 'fabsf64'?
   16 |         b = (mab + mib - _abs64(mab + mib) % 2) / 2;
      |                          ^~~~~~
      |                          fabsf64