Problem p02598 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
#define f first
#define s second
#define fore(i, a, b) for (int i = (a), ThxMK = (b); i < ThxMK; ++i)
#define pb push_back
#define all(s) begin(s), end(s)
#define _                                                                      \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define sz(s) int(s.size())
#define ENDL '\n'
using namespace std;
typedef long double ld;
typedef long long lli;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<lli> vl;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
#define deb(x) cout << #x ": " << (x) << endl;

const int N = 1e3;
const lli INF = 1e18;
const lli MOD = 1e9 + 7;

vi m;
vi primes(1, 2);
vector<vector<ld>> nk;
void sieve() {
  m = vi(N + 1, 0);
  for (int i = 4; i < N; i += 2)
    m[i] = 1;
  for (int i = 3; i * i <= N; i += 2)
    if (!m[i])
      for (int j = i * i; j < N; j += i)
        m[j] = 1;
  for (int i = 3; i < N; i += 2)
    if (!m[i])
      primes.pb(i);
}

void pascal() {
  nk = vector<vector<ld>>(N, vector<ld>(N, 0.0));
  fore(i, 0, N) nk[i][0] = nk[i][i] = 1.0;
  fore(i, 1, N) fore(j, 1, i) nk[i][j] = nk[i - 1][j - 1] + nk[i - 1][j];
}

lli gcd(lli a, lli b) { return (b ? gcd(b, a % b) : a); }

lli lcm(lli a, lli b) {
  if (a < b)
    swap(a, b);
  lli c = gcd(a, b);
  a /= c;
  return a * b;
}

int popcount(lli x) { return __builtin_popcountll(x); }

lli poww(lli a, lli b) {
  lli res = 1;
  while (b) {
    if (b & 1)
      res = res * a;
    a = a * a;
    b /= 2;
  }
  return res;
}

lli powm(lli a, lli b, lli mod = MOD) {
  lli res = 1;
  while (b) {
    if (b & 1)
      res = (res * a) % mod;
    a = (a * a) % mod;
    b /= 2;
  }
  return res;
}

bool isPrime(lli x) {
  if (x == 1)
    return 0;
  for (auto i : primes) {
    if (i * i > x)
      return 1;
    if (x % i == 0)
      return 0;
  }
  return 1;
}

// ---- コーディングはここから！ ('-')7

int main() {
  _ lli n, k;
  cin >> n >> k;
  vl v(n);
  fore(i, 0, n) cin >> v[i];
  sort(all(v), greater<lli>());
  lli L = 0, R = v[0], last = R;
  auto f = [&](lli mid) {
    lli r = 0;
    fore(i, 0, n) {
      if (v[i] <= mid)
        break;
      r += (v[i] / mid);
      if (v[i] % mid == 0)
        r--;
    }
    return r <= k;
  };
  while (L <= R) {
    lli mid = (L + R) / 2;
    if (f(mid))
      R = mid - 1, last = mid;
    else
      L = mid + 1;
  }
  cout << last << ENDL;
}


Fixed submission:
#include <bits/stdc++.h>
#define f first
#define s second
#define fore(i, a, b) for (int i = (a), ThxMK = (b); i < ThxMK; ++i)
#define pb push_back
#define all(s) begin(s), end(s)
#define _                                                                      \
  ios_base::sync_with_stdio(0);                                                \
  cin.tie(0);                                                                  \
  cout.tie(0);
#define sz(s) int(s.size())
#define ENDL '\n'
using namespace std;
typedef long double ld;
typedef long long lli;
typedef pair<int, int> ii;
typedef vector<int> vi;
typedef vector<lli> vl;
typedef vector<ii> vii;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
#define deb(x) cout << #x ": " << (x) << endl;

const int N = 1e3;
const lli INF = 1e18;
const lli MOD = 1e9 + 7;

vi m;
vi primes(1, 2);
vector<vector<ld>> nk;
void sieve() {
  m = vi(N + 1, 0);
  for (int i = 4; i < N; i += 2)
    m[i] = 1;
  for (int i = 3; i * i <= N; i += 2)
    if (!m[i])
      for (int j = i * i; j < N; j += i)
        m[j] = 1;
  for (int i = 3; i < N; i += 2)
    if (!m[i])
      primes.pb(i);
}

void pascal() {
  nk = vector<vector<ld>>(N, vector<ld>(N, 0.0));
  fore(i, 0, N) nk[i][0] = nk[i][i] = 1.0;
  fore(i, 1, N) fore(j, 1, i) nk[i][j] = nk[i - 1][j - 1] + nk[i - 1][j];
}

lli gcd(lli a, lli b) { return (b ? gcd(b, a % b) : a); }

lli lcm(lli a, lli b) {
  if (a < b)
    swap(a, b);
  lli c = gcd(a, b);
  a /= c;
  return a * b;
}

int popcount(lli x) { return __builtin_popcountll(x); }

lli poww(lli a, lli b) {
  lli res = 1;
  while (b) {
    if (b & 1)
      res = res * a;
    a = a * a;
    b /= 2;
  }
  return res;
}

lli powm(lli a, lli b, lli mod = MOD) {
  lli res = 1;
  while (b) {
    if (b & 1)
      res = (res * a) % mod;
    a = (a * a) % mod;
    b /= 2;
  }
  return res;
}

bool isPrime(lli x) {
  if (x == 1)
    return 0;
  for (auto i : primes) {
    if (i * i > x)
      return 1;
    if (x % i == 0)
      return 0;
  }
  return 1;
}

// ---- コーディングはここから！ ('-')7

int main() {
  _ lli n, k;
  cin >> n >> k;
  vl v(n);
  fore(i, 0, n) cin >> v[i];
  sort(all(v), greater<lli>());
  lli L = 1, R = v[0], last = R;
  auto f = [&](lli mid) {
    lli r = 0;
    fore(i, 0, n) {
      if (v[i] <= mid)
        break;
      r += (v[i] / mid);
      if (v[i] % mid == 0)
        r--;
    }
    return r <= k;
  };
  while (L <= R) {
    lli mid = (L + R) / 2;
    if (f(mid))
      R = mid - 1, last = mid;
    else
      L = mid + 1;
  }
  cout << last << ENDL;
}