Problem p02289 (C++) — buggy submission, verdict: Time Limit Exceeded

#define _USE_MATH_DEFINES
#include <algorithm>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

#define rep(i, N) for (int i = 0; i < N; i++)
#define pb push_back

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<int, ll> i_ll;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
typedef vector<int> vi;
struct edge {
  int v;
  ll w;
};

const int MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;
ll INF = INT_MAX;

struct skew_heap {
  skew_heap *lch, *rch;
  int val;
  skew_heap(int _val) : lch(NULL), rch(NULL), val(_val) {}
};

skew_heap *meld(skew_heap *x, skew_heap *y) {
  if (!x)
    return y;
  if (!y)
    return x;
  if (x->val < y->val)
    swap(x, y);
  x->rch = meld(x->rch, y);
  swap(x->lch, x->rch);
  return x;
}

skew_heap *push(skew_heap *x, int val) { return meld(x, new skew_heap(val)); }

skew_heap *pop(skew_heap *x) {
  return meld(x->lch, x->rch);
  skew_heap *y = meld(x->lch, x->rch);
  delete x;
  return y;
}

int main() {
  skew_heap *pq = NULL;
  for (;;) {
    char s[10];
    scanf("%s", s);
    if (s[2] == 's') {
      int x;
      scanf("%d", &x);
      pq = push(pq, x);
    }
    if (s[2] == 't') {
      printf("%d\\n", pq->val);
      pq = pop(pq);
    }
    if (s[2] == 'd')
      break;
  }
}

Error: TLE

Fixed submission:

#define _USE_MATH_DEFINES
#include <algorithm>
#include <cassert>
#include <cfloat>
#include <climits>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <functional>
#include <iostream>
#include <map>
#include <queue>
#include <random>
#include <set>
#include <sstream>
#include <stack>
#include <string>
#include <time.h>
#include <vector>
using namespace std;

#define rep(i, N) for (int i = 0; i < N; i++)
#define pb push_back

typedef long long ll;
typedef unsigned long long ull;
typedef pair<int, int> i_i;
typedef pair<ll, int> ll_i;
typedef pair<int, ll> i_ll;
typedef pair<double, int> d_i;
typedef pair<ll, ll> ll_ll;
typedef pair<double, double> d_d;
typedef vector<int> vi;
struct edge {
  int v;
  ll w;
};

const int MOD = 1000000007;
ll _MOD = 1000000009;
double EPS = 1e-10;
ll INF = INT_MAX;

struct skew_heap {
  skew_heap *lch, *rch;
  int val;
  skew_heap(int _val) : lch(NULL), rch(NULL), val(_val) {}
};

skew_heap *meld(skew_heap *x, skew_heap *y) {
  if (!x)
    return y;
  if (!y)
    return x;
  if (x->val < y->val)
    swap(x, y);
  x->rch = meld(x->rch, y);
  // swap(x->lch, x->rch);
  return x;
}

skew_heap *push(skew_heap *x, int val) { return meld(x, new skew_heap(val)); }

skew_heap *pop(skew_heap *x) {
  skew_heap *y = meld(x->lch, x->rch);
  delete x;
  return y;
}

int main() {
  skew_heap *pq = NULL;
  for (;;) {
    char s[10];
    scanf("%s", s);
    if (s[2] == 's') {
      int x;
      scanf("%d", &x);
      pq = push(pq, x);
    }
    if (s[2] == 't') {
      printf("%d\\n", pq->val);
      pq = pop(pq);
    }
    if (s[2] == 'd')
      break;
  }
}