Problem p02630 (C++) — buggy submission, verdict: Time Limit Exceeded

// 22-6-20
#pragma GCC optimize("-O2")
#define _CRT_SECURE_NO_WARNINGS 1

#include "bits/stdc++.h"
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
using namespace std ::chrono;

#define scu(n) scanf("%u", &n)
#define scl(n) scanf("%d", &n)
#define scll(n) scanf("%lld", &n)
#define sz(a) (int)a.size()
#define maxN 10000005
#define uu first
#define vv second
#define ll unsigned long long
#define U unsigned
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define vi vector<int>
#define mii map<int, int>
#define Pi acos(-1.0)
#define endl "\\n"
#define pqb priority_queue<int>
#define pqs priority_queue<int, vi, greater<int>>
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf 1e18
#define EPS 1e-9
#define ps(x, y) fixed << setprecision(y) << x
#define mk(arr, n, type) type *arr = new type[n];
#define TEST                                                                   \\
  int tc;                                                                      \\
  cin >> tc;                                                                   \\
  while (tc--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    pbds;

// Vector Macros
#define pb push_back
#define eb emplace_back
#define ALL(v) v.begin(), v.end()
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
#define MIN(c) *min_element(ALL(c))
#define MAX(c) *max_element(ALL(c))
#define SUM(c) accumulate(ALL(c), 0)

// Loop Macros
#define For(i, a, b) for (ll i = a; i <= b; i++)
#define rep(i, a, b) for (int i = a; i <= b; i++)
#define fr(i, n) for (ll i = 0; i < n; i++)

// Debug Macros
#define open freopen("input.txt", "r", stdin);
#define close freopen("output.txt", "w", stdout);
#define deb(a) cout << #a << " : " << a << " ";
#define debln(a) cout << #a << " : " << a << endl;
// Print Macros
#define print(v)                                                               \\
  for (auto x : v) {                                                           \\
    cout << x << " ";                                                          \\
  }                                                                            \\
  cout << endl;
#define PRINT(v)                                                               \\
  for (auto x : v) {                                                           \\
    cout << x.uu << " " << x.vv << endl;                                       \\
  }

/*
Time Calculation :
auto st = high_resolution_clock::now();
auto en = high_resolution_clock::now();
auto duration = duration_cast < milliseconds > (en-st);
cout<< "consumed time in ms " << duration.count() <<endl;
*/

/*

*/

void solve() {
  int n, q, b, c, i;
  cin >> n;

  int arr[100001] = {0};
  ll sum = 0;

  for (i = 0; i < n; ++i) {
    int x;
    cin >> x;

    arr[x]++;
    sum += x;
  }

  cin >> q;
  while (q--) {
    cin >> b >> c;

    int occurance = arr[b];
    arr[b] = 0;

    sum += (c - b) * occurance;
    arr[c] += occurance;

    cout << sum << endl;
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  solve();

  return 0;
}


Error: TLE

Fixed submission:

// 22-6-20
#pragma GCC optimize("-O2")
#define _CRT_SECURE_NO_WARNINGS 1

#include "bits/stdc++.h"
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
using namespace std ::chrono;

#define scu(n) scanf("%u", &n)
#define scl(n) scanf("%d", &n)
#define scll(n) scanf("%lld", &n)
#define sz(a) (int)a.size()
#define maxN 10000005
#define uu first
#define vv second
#define ll unsigned long long
#define U unsigned
#define pb push_back
#define mp make_pair
#define pii pair<int, int>
#define vi vector<int>
#define mii map<int, int>
#define Pi acos(-1.0)
#define endl "\\n"
#define pqb priority_queue<int>
#define pqs priority_queue<int, vi, greater<int>>
#define setbits(x) __builtin_popcountll(x)
#define zrobits(x) __builtin_ctzll(x)
#define mod 1000000007
#define inf 1e18
#define EPS 1e-9
#define ps(x, y) fixed << setprecision(y) << x
#define mk(arr, n, type) type *arr = new type[n];
#define TEST                                                                   \\
  int tc;                                                                      \\
  cin >> tc;                                                                   \\
  while (tc--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

typedef tree<int, null_type, less<int>, rb_tree_tag,
             tree_order_statistics_node_update>
    pbds;

// Vector Macros
#define pb push_back
#define eb emplace_back
#define ALL(v) v.begin(), v.end()
#define UNIQUE(v) v.erase(unique(ALL(v)), v.end())
#define MIN(c) *min_element(ALL(c))
#define MAX(c) *max_element(ALL(c))
#define SUM(c) accumulate(ALL(c), 0)

// Loop Macros
#define For(i, a, b) for (ll i = a; i <= b; i++)
#define rep(i, a, b) for (int i = a; i <= b; i++)
#define fr(i, n) for (ll i = 0; i < n; i++)

// Debug Macros
#define open freopen("input.txt", "r", stdin);
#define close freopen("output.txt", "w", stdout);
#define deb(a) cout << #a << " : " << a << " ";
#define debln(a) cout << #a << " : " << a << endl;
// Print Macros
#define print(v)                                                               \\
  for (auto x : v) {                                                           \\
    cout << x << " ";                                                          \\
  }                                                                            \\
  cout << endl;
#define PRINT(v)                                                               \\
  for (auto x : v) {                                                           \\
    cout << x.uu << " " << x.vv << endl;                                       \\
  }

/*
Time Calculation :
auto st = high_resolution_clock::now();
auto en = high_resolution_clock::now();
auto duration = duration_cast < milliseconds > (en-st);
cout<< "consumed time in ms " << duration.count() <<endl;
*/

/*

*/

void solve() {
  int n, q, b, c, i;
  cin >> n;

  multiset<ll> st;
  ll sum = 0;

  for (i = 0; i < n; ++i) {
    ll input;
    cin >> input;
    st.insert(input);

    sum += input;
  }

  cin >> q;
  while (q--) {
    cin >> b >> c;

    ll occurance = st.count(b);

    st.erase(b);
    for (i = 0; i < occurance; ++i)
      st.insert(c);

    sum += (c - b) * occurance;
    cout << sum << endl;
  }
}

int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);

  solve();

  return 0;
}