Problem p02580 (C++) — buggy submission, verdict: Runtime Error

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ll long long
#define hii cout << "hii" << endl
#define int long long
#define endl '\\n'
#define all(s) s.begin(), s.end()

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (T i : v)
    os << i << ' ';
  return os;
}
template <class T> ostream &operator<<(ostream &os, const set<T> &v) {
  for (T i : v)
    os << i << ' ';
  return os;
}
template <class T, class S>
ostream &operator<<(ostream &os, const pair<T, S> &v) {
  os << v.first << ' ' << v.second;
  return os;
}
template <class T, class S>
ostream &operator<<(ostream &os, const unordered_map<T, S> &v) {
  for (auto i : v)
    os << '(' << i.first << "=>" << i.second << ')' << ' ';
  return os;
}

#ifndef ONLINE_JUDGE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <class Arg1> void __f(const char *name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << endl;
}
template <class Arg1, class... Args>
void __f(const char *names, Arg1 &&arg1, Args &&...args) {
  const char *sep = strchr(names + 1, ',');
  cerr.write(names, sep - names) << " : " << arg1 << "  ";
  __f(sep + 1, args...);
}
#else
#define trace(...) 0
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target(                                                            \\
    "avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define _CRT_SECURE_NO_WARNINGS
#endif // ifndef ONLINE_JUDGE

const int N = 5e5 + 5;
const int MAX = 250000 + 5;
const int M = 5e6 + 5;
const int mod = 1e9 + 7;
const int MOD = 998244353;
const int INF = 1e15;
const int LG = 21;

int col[N];
vector<int> row[N];

void solve() {
  int h, w, m;
  cin >> h >> w >> m;
  set<pair<int, int>> s;
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    row[a].push_back(b);
    col[b]++;
  }
  for (int i = 1; i < N; i++) {
    if (col[i]) {
      s.insert({col[i], i});
    }
  }
  int ret = 0;
  for (int i = 1; i < N; i++) {
    for (auto x : row[i]) {
      s.erase({col[x], x});
      col[x]--;
      s.insert({col[x], x});
    }
    auto it = s.end();
    it--;
    int temp = row[i].size() + it->first;
    ret = max(ret, temp);
    for (auto x : row[i]) {
      s.erase({col[x], x});
      col[x]++;
      s.insert({col[x], x});
    }
  }
  cout << ret << endl;
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);

  int t = 1;
  // cin >> t;
  while (t--)
    solve();
  return 0;
}

Error: 0

Fixed submission:

#include <bits/stdc++.h>
using namespace std;
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
#define ll long long
#define hii cout << "hii" << endl
#define int long long
#define endl '\\n'
#define all(s) s.begin(), s.end()

template <class T> ostream &operator<<(ostream &os, const vector<T> &v) {
  for (T i : v)
    os << i << ' ';
  return os;
}
template <class T> ostream &operator<<(ostream &os, const set<T> &v) {
  for (T i : v)
    os << i << ' ';
  return os;
}
template <class T, class S>
ostream &operator<<(ostream &os, const pair<T, S> &v) {
  os << v.first << ' ' << v.second;
  return os;
}
template <class T, class S>
ostream &operator<<(ostream &os, const unordered_map<T, S> &v) {
  for (auto i : v)
    os << '(' << i.first << "=>" << i.second << ')' << ' ';
  return os;
}

#ifndef ONLINE_JUDGE
#define trace(...) __f(#__VA_ARGS__, __VA_ARGS__)
template <class Arg1> void __f(const char *name, Arg1 &&arg1) {
  cerr << name << " : " << arg1 << endl;
}
template <class Arg1, class... Args>
void __f(const char *names, Arg1 &&arg1, Args &&...args) {
  const char *sep = strchr(names + 1, ',');
  cerr.write(names, sep - names) << " : " << arg1 << "  ";
  __f(sep + 1, args...);
}
#else
#define trace(...) 0
#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")
#pragma GCC target(                                                            \\
    "avx2,sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define _CRT_SECURE_NO_WARNINGS
#endif // ifndef ONLINE_JUDGE

const int N = 5e5 + 5;
const int MAX = 250000 + 5;
const int M = 5e6 + 5;
const int mod = 1e9 + 7;
const int MOD = 998244353;
const int INF = 1e15;
const int LG = 21;

int col[N];
vector<int> row[N];

void solve() {
  int h, w, m;
  cin >> h >> w >> m;
  set<pair<int, int>> s;
  for (int i = 0; i < m; i++) {
    int a, b;
    cin >> a >> b;
    row[a].push_back(b);
    col[b]++;
  }
  for (int i = 1; i <= N; i++) {
    if (col[i]) {
      s.insert({col[i], i});
    }
  }
  int ret = 0;
  for (int i = 1; i <= N; i++) {
    for (auto x : row[i]) {
      s.erase({col[x], x});
      col[x]--;
      s.insert({col[x], x});
    }
    auto it = s.end();
    it--;
    int temp = row[i].size() + it->first;
    ret = max(ret, temp);
    for (auto x : row[i]) {
      s.erase({col[x], x});
      col[x]++;
      s.insert({col[x], x});
    }
  }
  cout << ret << endl;
}

int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  cout.tie(NULL);

  int t = 1;
  // cin >> t;
  while (t--)
    solve();
  return 0;
}