Problem p02598 (C++)

Buggy submission (status: Runtime Error):

#include <bits/stdc++.h>
using namespace std;
/**
******************* Author:Bisnu sarkar ****************************
**/
/*
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
*/
#define fRead(x) freopen(x, "r", stdin)
#define fWrite(x) freopen(x, "w", stdout)
#define ull unsigned long long
#define ll long long
#define pii pair<int, int>
#define sit set<int>::iterator
#define vrit vector<int>::reverse iterator
#define ff first
#define ss second
#define endl '\n';
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define IO ios_base::sync_with_stdio(false), cin.tie(NULL);
#define what_is(x) cerr << #x << " is " << x << endl;
///*....Debugger....*///
#define error(args...)                                                         \
  {                                                                            \
    string _s = #args;                                                         \
    replace(_s.begin(), _s.end(), ',', ' ');                                   \
    stringstream _ss(_s);                                                      \
    istream_iterator<string> _it(_ss);                                         \
    err(_it, args);                                                            \
  }
void err(istream_iterator<string> it) { cout << endl; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << ", ";
  err(++it, args...);
}
///*....Input....*///
template <typename T> inline void Int(T &n) {
  n = 0;
  int f = 1;
  register int ch = getchar();
  for (; !isdigit(ch); ch = getchar())
    if (ch == '-')
      f = -1;
  for (; isdigit(ch); ch = getchar())
    n = (n << 3) + (n << 1) + ch - '0';
  n = n * f;
}

template <typename T, typename TT> inline void Int(T &n, TT &m) {
  Int(n);
  Int(m);
}
template <typename T, typename TT, typename TTT>
inline void Int(T &n, TT &m, TTT &l) {
  Int(n, m);
  Int(l);
}
double ind() {
  double x;
  scanf("%lf", &x);
  return x;
}

///*....Bitmask....*///
int set_1(int n, int pos) { return n = (n | (1 << pos)); }
int reset_0(int n, int pos) { return n = n & ~(1 << pos); }
bool check_bit(int n, int pos) { return n = n & (1 << pos); }

int dx[8] = {1, 0, -1, 0, -1, -1, 1, 1};
int dy[8] = {0, 1, 0, -1, -1, 1, -1, 1};

///*....Constraints....*///
const int N = (int)1e6 + 5;
const int M = (int)1e9 + 7;
const double pi = 2 * acos(0.0);
const double eps = 1e-9;

ll a[N];
ll n, k;
bool valid(ll x) {
  ll op = 0ll;
  for (int i = 1; i <= n; ++i) {
    ll p = a[i] / x;
    if (a[i] % x == 0)
      p -= 1;
    op += p;
    //   error(a[i],x,p)
  }
  return op <= k;
}

int main() {

  Int(n, k);
  ll ma = 0ll;

  for (int i = 1; i <= n; ++i) {
    Int(a[i]);
    ma = max(a[i], ma);
  }

  ll l = 0, r = ma, ans;

  while (l <= r) {
    ll mid = (l + r) / 2;

    if (valid(mid)) {
      ans = mid;
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  printf("%lld\n", ans);

  return 0;
}


Fixed submission:

#include <bits/stdc++.h>
using namespace std;
/**
******************* Author:Bisnu sarkar ****************************
**/
/*
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
*/
#define fRead(x) freopen(x, "r", stdin)
#define fWrite(x) freopen(x, "w", stdout)
#define ull unsigned long long
#define ll long long
#define pii pair<int, int>
#define sit set<int>::iterator
#define vrit vector<int>::reverse iterator
#define ff first
#define ss second
#define endl '\n';
#define sz(s) (int)s.size()
#define all(s) s.begin(), s.end()
#define IO ios_base::sync_with_stdio(false), cin.tie(NULL);
#define what_is(x) cerr << #x << " is " << x << endl;
///*....Debugger....*///
#define error(args...)                                                         \
  {                                                                            \
    string _s = #args;                                                         \
    replace(_s.begin(), _s.end(), ',', ' ');                                   \
    stringstream _ss(_s);                                                      \
    istream_iterator<string> _it(_ss);                                         \
    err(_it, args);                                                            \
  }
void err(istream_iterator<string> it) { cout << endl; }
template <typename T, typename... Args>
void err(istream_iterator<string> it, T a, Args... args) {
  cerr << *it << " = " << a << ", ";
  err(++it, args...);
}
///*....Input....*///
template <typename T> inline void Int(T &n) {
  n = 0;
  int f = 1;
  register int ch = getchar();
  for (; !isdigit(ch); ch = getchar())
    if (ch == '-')
      f = -1;
  for (; isdigit(ch); ch = getchar())
    n = (n << 3) + (n << 1) + ch - '0';
  n = n * f;
}

template <typename T, typename TT> inline void Int(T &n, TT &m) {
  Int(n);
  Int(m);
}
template <typename T, typename TT, typename TTT>
inline void Int(T &n, TT &m, TTT &l) {
  Int(n, m);
  Int(l);
}
double ind() {
  double x;
  scanf("%lf", &x);
  return x;
}

///*....Bitmask....*///
int set_1(int n, int pos) { return n = (n | (1 << pos)); }
int reset_0(int n, int pos) { return n = n & ~(1 << pos); }
bool check_bit(int n, int pos) { return n = n & (1 << pos); }

int dx[8] = {1, 0, -1, 0, -1, -1, 1, 1};
int dy[8] = {0, 1, 0, -1, -1, 1, -1, 1};

///*....Constraints....*///
const int N = (int)1e6 + 5;
const int M = (int)1e9 + 7;
const double pi = 2 * acos(0.0);
const double eps = 1e-9;

ll a[N];
ll n, k;
bool valid(ll x) {
  ll op = 0ll;
  for (int i = 1; i <= n; ++i) {
    ll p = a[i] / x;
    if (a[i] % x == 0)
      p -= 1;
    op += p;
    //   error(a[i],x,p)
  }
  return op <= k;
}

int main() {

  Int(n, k);
  ll ma = 0ll;

  for (int i = 1; i <= n; ++i) {
    Int(a[i]);
    ma = max(a[i], ma);
  }

  ll l = 1, r = ma, ans;

  while (l <= r) {
    ll mid = (l + r) / 2;

    if (valid(mid)) {
      ans = mid;
      r = mid - 1;
    } else {
      l = mid + 1;
    }
  }
  printf("%lld\n", ans);

  return 0;
}