Problem p02598 (C++) — buggy submission, verdict: Runtime Error


// Problem : E - Logs
// Contest : AtCoder - AtCoder Beginner Contest 174
// URL : https://atcoder.jp/contests/abc174/tasks/abc174_e
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

/* ID: vqt
LANG: C++14
PROB: namenum
*/

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")

#include <bits/stdc++.h>
#include <unistd.h>
using namespace std;

// for PDBS use only:
//  #include <ext/pb_ds/assoc_container.hpp>
//  #include <ext/pb_ds/tree_policy.hpp>
//  using namespace __gnu_pbds;
//  template <typename T> using o_set = tree<T, null_type, greater<T>,
//  rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
// #define ordered_set tree<pair<ll,ll>, null_type,less<pair<ll,ll>>,
// rb_tree_tag,tree_order_statistics_node_update>

// defines
#define int long long
// #define double long double
#define vec vector
#define vi vector<int>
#define vvi vector<vector<int>>
#define ii pair<int, int>
#define F first
#define S second
#define MP make_pair
#define vii vector<ii>
#define PQ priority_queue
#define minPQ priority_queue<int, vt<int>, greater<int>>
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define ER equal_range
#define ALL(x) begin(x), end(x)
#define SZ(x) ((int)(x).size())
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define FORE(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (a); i >= (b); i--)
#define UNI(c) c.resize(distance(c.begin(), unique(c.begin(), c.end())));
#define SORT_UNI(c)                                                            \\
  (sort(c.begin(), c.end()),                                                   \\
   c.resize(distance(c.begin(), unique(c.begin(), c.end()))))
#define POS(c, x) (lower_bound(c.begin(), c.end(), (x)) - c.begin())
#define max(a, b) ((a) < (b) ? b : a)
#define min(a, b) ((a) < (b) ? a : b)
#define setmin(a, b) a = min(a, b)
#define setmax(a, b) a = max(a, b)
#define MINMAX(x) minmax_element(begin(x), end(x))

// permanent constants
const long long INF64 = 1e18;
const int INF32 = 1e9;
const double EPS = static_cast<double>(1e-10);
const double PI = 2.0 * acos(0.0); // acos(-1.0L);
const int MOD = (int)1e9 + 7;      // 998244353
ll powMod(ll a, ll b) {
  ll res = 1;
  a %= MOD;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1)
      res = res * a % MOD;
    a = a * a % MOD;
  }
  return res;
}
ll invMod(ll a) {
  ll b = MOD, u = 1, v = 0;
  while (b) {
    ll t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  return (MOD + u) % MOD;
}
const int day[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

// random
mt19937 rnd(
    239); //(chrono::high_resolution_clock::now().time_since_epoch().count());

// Tricks:
//  Sort w Lambda Function: sort(begin(v), end(v), [] (int a, int b) { return a
//  > b; }); Sort vector cua bo ba so: struct MyStr {int a, b, c;};
//  vector<MyStr> v; ...fill v... sort(all(v), [](MyStr &A, MyStr &B) { return
//  tie(A.a, A.b, A.c) < tie(B.a, B.b, B.c); });
#define odd(x) ((x)&1)
#define even(x) !((x)&1)
// vec - vector, p(x) - predicate so that p(x) = true for all elements of some
// prefix of vector vec and false on all others. To find the first place where
// p(x) doesn't hold one can simply use:
#define FIRST_FAIL(vec, p) partition_point(ALL(vec), p) - vec.begin()
// partition_point(begin, end, p) returns the first ITERATOR it that p(*it) =
// false
#define isIn(vec, key) binary_search(ALL(vec), key)
#define toBool(num) !!(num)
#define bin(N, num) cerr << bitset<N>(num) << "\\n"
// vector a: tinh XOR sum tu l den r:
#define XORsum(a, l, r)                                                        \\
  accumulate(a.begin() + l - 1, a.begin() + r, 0,                              \\
             [](int x, int y) { return x ^ y; })
// BASIC STRING: just like vector but allows to use a few string member
// functions/operators: operator+ and operator+=.:
/*  int n;    basic_string<int> a;
    cin >> n; FOR(i, 0, n) { int x;   cin >> x; a += x; }
    a += a; a = a.substr(n/2, n);
    cout << (a + a).find({1, 2, 1}) << '\\n';
*/
// count(a.begin(), a.end(), val) - count how many val in an array a
vector<int> prefixSum(vector<int> &a) {
  vi b;
  std::partial_sum(a.begin(), a.end(), b.begin());
  return b;
}

int mostSignDigit(int n) {
  double k = log10(n);
  return (int)pow(10, k - floor(k));
}
int numOfDigits(int n) { return (int)floor(log10(n)) + 1; }
bool isPowerOfTwo(int x) {
  return x && (!(x & (x - 1)));
} // first x is for the case x=0

bool allPositive(vector<int> &a) {
  return all_of(begin(a), end(a), [](int x) { return x > 0; });
} // are all of the elements positive?
// CHECK there is all numbers in array is positive: bool ok=true; for(auto z: a)
// ok &= (z>0);
bool anyPositive(vector<int> &a) {
  return any_of(begin(a), end(a), [](int x) { return x > 0; });
} // is there at least one positive element?
bool nonePositive(vector<int> &a) {
  return none_of(begin(a), end(a), [](int x) { return x > 0; });
} // are none of the elements positive?

void FILEIO() {
  freopen("in.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
}
// void FILEIO() {  freopen("berries.in", "r", stdin);  freopen("berries.out",
// "w", stdout); } // USACO

/****************** DEBUG *******************/
// Universal DEBUG: https://codeforces.com/blog/entry/68809
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
// void __print(long long x) {cerr << x;}
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\\'' << x << '\\''; }
void __print(const char *x) { cerr << '\\"' << x << '\\"'; }
void __print(const string &x) { cerr << '\\"' << x << '\\"'; }
void __print(bool x) { cerr << (x ? "T" : "F"); }
template <typename T, typename V> void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T> void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x)
    cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\\n"; }
template <typename T, typename... V> void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v))
    cerr << ", ";
  _print(v...);
}

// #define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
#define debug(x...)                                                            \\
  cerr << "[" << #x << "] = [";                                                \\
  _print(x)
#else
#define debug(x...)
#endif
//********************** Codes go here *********************/
int n, k;
vi a;

bool ok(int m) { // can divide to <=m, by <=k cuts
  int cnt = 0;
  FOR(i, 0, n) { cnt += (a[i] + m - 1) / m - 1; }
  if (cnt <= k)
    return true;
  return false;
}

void solve() {
  cin >> n >> k;
  a.resize(n);
  FOR(i, 0, n) cin >> a[i];
  int sum = 0;
  FOR(i, 0, n) sum += a[i] - 1;
  if (k >= sum) {
    cout << 1 << endl;
    return;
  }
  int lo = 0, hi = (int)1e9 + 2;
  while (hi - lo > 1) {
    int mid = (lo + hi) / 2;

    // debug(lo, hi, mid, ok(mid));

    if (ok(mid))
      hi = mid;
    else
      lo = mid;
  }

  // debug(lo, hi, ok(lo), ok(hi));

  if (ok(lo)) {
    cout << lo << endl;
    return;
  }
  cout << hi << endl;
}

signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie();
  // FILEIO();
  //  auto beginProgram = chrono::steady_clock::now();

  // preCalc(); // any 1-time precalculation need to do before many test cases?

  // int t; cin >> t; FORE(i, 1, t)
  {
    // cout << "Case #" << i << ": "; // Google CodeJam style
    solve();
  }

  //  auto endProgram = chrono::steady_clock::now();
  //  cerr << chrono::duration_cast<chrono::milliseconds>(endProgram -
  //  beginProgram).count() << " ms" << endl;
  return 0;
}

Error: 0
[lo, hi, mid, ok(mid)] = [0, 1000000002, 500000001, T]
[lo, hi, mid, ok(mid)] = [0, 500000001, 250000000, T]
[lo, hi, mid, ok(mid)] = [0, 250000000, 125000000, T]
[lo, hi, mid, ok(mid)] = [0, 125000000, 62500000, T]
[lo, hi, mid, ok(mid)] = [0, 62500000, 31250000, T]
[lo, hi, mid, ok(mid)] = [0, 31250000, 15625000, T]
[lo, hi, mid, ok(mid)] = [0, 15625000, 7812500, T]
[lo, hi, mid, ok(mid)] = [0, 7812500, 3906250, T]
[lo, hi, mid, ok(mid)] = [0, 3906250, 1953125, T]
[lo, hi, mid, ok(mid)] = [0, 1953125, 976562, T]
[lo, hi, mid, ok(mid)] = [0, 976562, 488281, T]
[lo, hi, mid, ok(mid)] = [0, 488281, 244140, T]
[lo, hi, mid, ok(mid)] = [0, 244140, 122070, T]
[lo, hi, mid, ok(mid)] = [0, 122070, 61035, T]
[lo, hi, mid, ok(mid)] = [0, 61035, 30517, T]
[lo, hi, mid, ok(mid)] = [0, 30517, 15258, T]
[lo, hi, mid, ok(mid)] = [0, 15258, 7629, T]
[lo, hi, mid, ok(mid)] = [0, 7629, 3814, T]
[lo, hi, mid, ok(mid)] = [0, 3814, 1907, T]
[lo, hi, mid, ok(mid)] = [0, 1907, 953, T]
[lo, hi, mid, ok(mid)] = [0, 953, 476, T]
[lo, hi, mid, ok(mid)] = [0, 476, 238, T]
[lo, hi, mid, ok(mid)] = [0, 238, 119, T]
[lo, hi, mid, ok(mid)] = [0, 119, 59, T]
[lo, hi, mid, ok(mid)] = [0, 59, 29, T]
[lo, hi, mid, ok(mid)] = [0, 29, 14, T]
[lo, hi, mid, ok(mid)] = [0, 14, 7, T]
[lo, hi, mid, ok(mid)] = [0, 7, 3, F]
[lo, hi, mid, ok(mid)] = [3, 7, 5, T]
[lo, hi, mid, ok(mid)] = [3, 5, 4, T]
[lo, hi, ok(lo), ok(hi)] = [3, 4, F, T]


Fixed submission:


// Problem : E - Logs
// Contest : AtCoder - AtCoder Beginner Contest 174
// URL : https://atcoder.jp/contests/abc174/tasks/abc174_e
// Memory Limit : 1024 MB
// Time Limit : 2000 ms
// Powered by CP Editor (https://github.com/cpeditor/cpeditor)

/* ID: vqt
LANG: C++14
PROB: namenum
*/

#pragma GCC target("avx2")
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC optimize("Ofast")

#include <bits/stdc++.h>
#include <unistd.h>
using namespace std;

// for PDBS use only:
//  #include <ext/pb_ds/assoc_container.hpp>
//  #include <ext/pb_ds/tree_policy.hpp>
//  using namespace __gnu_pbds;
//  template <typename T> using o_set = tree<T, null_type, greater<T>,
//  rb_tree_tag, tree_order_statistics_node_update>;
typedef long long ll;
// #define ordered_set tree<pair<ll,ll>, null_type,less<pair<ll,ll>>,
// rb_tree_tag,tree_order_statistics_node_update>

// defines
#define int long long
// #define double long double
#define vec vector
#define vi vector<int>
#define vvi vector<vector<int>>
#define ii pair<int, int>
#define F first
#define S second
#define MP make_pair
#define vii vector<ii>
#define PQ priority_queue
#define minPQ priority_queue<int, vt<int>, greater<int>>
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define ER equal_range
#define ALL(x) begin(x), end(x)
#define SZ(x) ((int)(x).size())
#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define FORE(i, a, b) for (int i = (a); i <= (b); i++)
#define FORD(i, a, b) for (int i = (a); i >= (b); i--)
#define UNI(c) c.resize(distance(c.begin(), unique(c.begin(), c.end())));
#define SORT_UNI(c)                                                            \\
  (sort(c.begin(), c.end()),                                                   \\
   c.resize(distance(c.begin(), unique(c.begin(), c.end()))))
#define POS(c, x) (lower_bound(c.begin(), c.end(), (x)) - c.begin())
#define max(a, b) ((a) < (b) ? b : a)
#define min(a, b) ((a) < (b) ? a : b)
#define setmin(a, b) a = min(a, b)
#define setmax(a, b) a = max(a, b)
#define MINMAX(x) minmax_element(begin(x), end(x))

// permanent constants
const long long INF64 = 1e18;
const int INF32 = 1e9;
const double EPS = static_cast<double>(1e-10);
const double PI = 2.0 * acos(0.0); // acos(-1.0L);
const int MOD = (int)1e9 + 7;      // 998244353
ll powMod(ll a, ll b) {
  ll res = 1;
  a %= MOD;
  assert(b >= 0);
  for (; b; b >>= 1) {
    if (b & 1)
      res = res * a % MOD;
    a = a * a % MOD;
  }
  return res;
}
ll invMod(ll a) {
  ll b = MOD, u = 1, v = 0;
  while (b) {
    ll t = a / b;
    a -= t * b;
    swap(a, b);
    u -= t * v;
    swap(u, v);
  }
  return (MOD + u) % MOD;
}
const int day[12] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};

// random
mt19937 rnd(
    239); //(chrono::high_resolution_clock::now().time_since_epoch().count());

// Tricks:
//  Sort w Lambda Function: sort(begin(v), end(v), [] (int a, int b) { return a
//  > b; }); Sort vector cua bo ba so: struct MyStr {int a, b, c;};
//  vector<MyStr> v; ...fill v... sort(all(v), [](MyStr &A, MyStr &B) { return
//  tie(A.a, A.b, A.c) < tie(B.a, B.b, B.c); });
#define odd(x) ((x)&1)
#define even(x) !((x)&1)
// vec - vector, p(x) - predicate so that p(x) = true for all elements of some
// prefix of vector vec and false on all others. To find the first place where
// p(x) doesn't hold one can simply use:
#define FIRST_FAIL(vec, p) partition_point(ALL(vec), p) - vec.begin()
// partition_point(begin, end, p) returns the first ITERATOR it that p(*it) =
// false
#define isIn(vec, key) binary_search(ALL(vec), key)
#define toBool(num) !!(num)
#define bin(N, num) cerr << bitset<N>(num) << "\\n"
// vector a: tinh XOR sum tu l den r:
#define XORsum(a, l, r)                                                        \\
  accumulate(a.begin() + l - 1, a.begin() + r, 0,                              \\
             [](int x, int y) { return x ^ y; })
// BASIC STRING: just like vector but allows to use a few string member
// functions/operators: operator+ and operator+=.:
/*  int n;    basic_string<int> a;
    cin >> n; FOR(i, 0, n) { int x;   cin >> x; a += x; }
    a += a; a = a.substr(n/2, n);
    cout << (a + a).find({1, 2, 1}) << '\\n';
*/
// count(a.begin(), a.end(), val) - count how many val in an array a
vector<int> prefixSum(vector<int> &a) {
  vi b;
  std::partial_sum(a.begin(), a.end(), b.begin());
  return b;
}

int mostSignDigit(int n) {
  double k = log10(n);
  return (int)pow(10, k - floor(k));
}
int numOfDigits(int n) { return (int)floor(log10(n)) + 1; }
bool isPowerOfTwo(int x) {
  return x && (!(x & (x - 1)));
} // first x is for the case x=0

bool allPositive(vector<int> &a) {
  return all_of(begin(a), end(a), [](int x) { return x > 0; });
} // are all of the elements positive?
// CHECK there is all numbers in array is positive: bool ok=true; for(auto z: a)
// ok &= (z>0);
bool anyPositive(vector<int> &a) {
  return any_of(begin(a), end(a), [](int x) { return x > 0; });
} // is there at least one positive element?
bool nonePositive(vector<int> &a) {
  return none_of(begin(a), end(a), [](int x) { return x > 0; });
} // are none of the elements positive?

void FILEIO() {
  freopen("in.txt", "r", stdin);
  freopen("out.txt", "w", stdout);
}
// void FILEIO() {  freopen("berries.in", "r", stdin);  freopen("berries.out",
// "w", stdout); } // USACO

/****************** DEBUG *******************/
// Universal DEBUG: https://codeforces.com/blog/entry/68809
void __print(int x) { cerr << x; }
void __print(long x) { cerr << x; }
// void __print(long long x) {cerr << x;}
void __print(unsigned x) { cerr << x; }
void __print(unsigned long x) { cerr << x; }
void __print(unsigned long long x) { cerr << x; }
void __print(float x) { cerr << x; }
void __print(double x) { cerr << x; }
void __print(long double x) { cerr << x; }
void __print(char x) { cerr << '\\'' << x << '\\''; }
void __print(const char *x) { cerr << '\\"' << x << '\\"'; }
void __print(const string &x) { cerr << '\\"' << x << '\\"'; }
void __print(bool x) { cerr << (x ? "T" : "F"); }
template <typename T, typename V> void __print(const pair<T, V> &x) {
  cerr << '{';
  __print(x.first);
  cerr << ',';
  __print(x.second);
  cerr << '}';
}
template <typename T> void __print(const T &x) {
  int f = 0;
  cerr << '{';
  for (auto &i : x)
    cerr << (f++ ? "," : ""), __print(i);
  cerr << "}";
}
void _print() { cerr << "]\\n"; }
template <typename T, typename... V> void _print(T t, V... v) {
  __print(t);
  if (sizeof...(v))
    cerr << ", ";
  _print(v...);
}

// #define ONLINE_JUDGE
#ifndef ONLINE_JUDGE
#define debug(x...)                                                            \\
  cerr << "[" << #x << "] = [";                                                \\
  _print(x)
#else
#define debug(x...)
#endif
//********************** Codes go here *********************/
int n, k;
vi a;

bool ok(int m) { // can divide to <=m, by <=k cuts
  int cnt = 0;
  FOR(i, 0, n) { cnt += (a[i] + m - 1) / m - 1; }
  if (cnt <= k)
    return true;
  return false;
}

void solve() {
  cin >> n >> k;
  a.resize(n);
  FOR(i, 0, n) cin >> a[i];
  // if(k==0) {cout << *max_element(ALL(a)) << endl; return;}
  int lo = 0, hi = (int)1e9 + 2;
  while (hi - lo > 1) {
    int mid = (lo + hi) / 2;

    debug(lo, hi, mid, ok(mid));

    if (ok(mid))
      hi = mid;
    else
      lo = mid;
  }

  debug(lo, hi, ok(lo), ok(hi));

  if (ok(lo)) {
    cout << lo << endl;
    return;
  }
  cout << hi << endl;
}

signed main() {
  ios_base::sync_with_stdio(false);
  cin.tie();
  // FILEIO();
  //  auto beginProgram = chrono::steady_clock::now();

  // preCalc(); // any 1-time precalculation need to do before many test cases?

  // int t; cin >> t; FORE(i, 1, t)
  {
    // cout << "Case #" << i << ": "; // Google CodeJam style
    solve();
  }

  //  auto endProgram = chrono::steady_clock::now();
  //  cerr << chrono::duration_cast<chrono::milliseconds>(endProgram -
  //  beginProgram).count() << " ms" << endl;
  return 0;
}