Problem p00099 (C++) — buggy submission, verdict: Time Limit Exceeded

#define _CRT_SECURE_NO_WARNINGS 1
#include <algorithm>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define M_PI 3.141592
#define FOR(i, n) for (int i = 0; i < (int)n; i++)
#define FORI(i, k, n) for (int i = k; i < (int)n; i++)
#define toRad 2.0 * M_PI / 360.0
#define inin(x)                                                                \\
  int x;                                                                       \\
  cin >> x;
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << " :" << x << endl;
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define EPS 1e-12
#define pri_max 60000
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef vector<int> vi;
typedef vector<vi> vvi;
int a[1000001] = {};
int main() {
  set<pii, greater<pii>> s;
  set<pii, greater<pii>>::iterator it;
  int n, q;
  cin >> n >> q;
  for (int i = 0; i < q; i++) {
    pii now;
    cin >> now.second >> now.first;
    now.second = -now.second;

    it = s.find(pii(a[-now.second], now.second));

    a[-now.second] += now.first;

    if (it == s.end()) {
      s.insert(now);
    } else {
      s.erase(it);
      s.insert(pii(a[-now.second], now.second));
    }
    now = *s.begin();
    cout << -now.second << " " << now.first << endl;
    ;
  }
}

Error: TLE

Fixed submission:

#define _CRT_SECURE_NO_WARNINGS 1
#include <algorithm>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iomanip>
#include <iostream>
#include <list>
#include <map>
#include <queue>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define M_PI 3.141592
#define FOR(i, n) for (int i = 0; i < (int)n; i++)
#define FORI(i, k, n) for (int i = k; i < (int)n; i++)
#define toRad 2.0 * M_PI / 360.0
#define inin(x)                                                                \\
  int x;                                                                       \\
  cin >> x;
#define all(x) x.begin(), x.end()
#define debug(x) cout << #x << " :" << x << endl;
#define rep(i, n) for (int i = 0; i < (int)n; i++)
#define EPS 1e-12
#define pri_max 60000
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef vector<int> vi;
typedef vector<vi> vvi;
int a[1000001] = {};
int main() {
  set<pii, greater<pii>> s;
  set<pii, greater<pii>>::iterator it;
  int n, q;
  cin >> n >> q;
  for (int i = 0; i < q; i++) {
    pii now;
    bool ok = true;
    cin >> now.second >> now.first;
    now.second = -now.second;
    for (it = s.begin(); it != s.end(); it++) {
      pii x = *it;
      if (x.second == now.second) {
        now.first += x.first;
        s.erase(it);
        s.insert(now);
        ok = false;
        break;
      }
    }
    if (ok)
      s.insert(now);
    now = *s.begin();
    cout << -now.second << " " << now.first << endl;
  }
}