Problem p02361 (C++)

Buggy submission (status: Time Limit Exceeded):
#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i)
#define each(a, b) for (auto(a) : (b))
#define all(v) (v).begin(), (v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)), v.erase(unique(all(v)), v.end())
#define cmx(x, y) x = max(x, y)
#define cmn(x, y) x = min(x, y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout << #x << " = " << (x) << endl
#define spair(p) cout << #p << ": " << p.fi << " " << p.se << endl
#define svec(v)                                                                \
  cout << #v << ":";                                                           \
  rep(kbrni, v.size()) cout << " " << v[kbrni];                                \
  cout << endl
#define sset(s)                                                                \
  cout << #s << ":";                                                           \
  each(kbrni, s) cout << " " << kbrni;                                         \
  cout << endl
#define smap(m)                                                                \
  cout << #m << ":";                                                           \
  each(kbrni, m) cout << " {" << kbrni.first << ":" << kbrni.second << "}";    \
  cout << endl

using namespace std;

typedef pair<int, int> P;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

template <typename T> class Heap {
public:
  struct node {
    node *l;
    node *r;
    T val;
    node(T t) : l(nullptr), r(nullptr), val(t) {}
  };
  node *root;
  Heap() : root(nullptr) {}
  node *meld(node *a, node *b) {
    if (!a)
      return b;
    if (!b)
      return a;
    if (a->val < b->val)
      swap(a, b);
    a->r = meld(a->r, b);
    swap(a->l, a->r);
    return a;
  }
  void push(T val) {
    node *p = new node(val);
    root = meld(root, p);
  }
  T top() { return root->val; }
  void pop() {
    node *p = root;
    root = meld(root->r, root->l);
    delete p;
  }
};

struct edge {
  int to, cost;
};

int d[MAX_N];
vector<edge> G[MAX_N];

void dijkstra(int s) {
  Heap<P> que;
  d[s] = 0;
  que.push(P(0, s));
  while (que.root) {
    P p = que.top();
    que.pop();
    int v = p.second;
    if (d[v] < p.first)
      continue;
    for (auto w : G[v]) {
      if (d[w.to] > d[v] + w.cost) {
        d[w.to] = d[v] + w.cost;
        que.push(P(d[w.to], w.to));
      }
    }
  }
}

int main() {
  int n, m, s;
  scanf("%d%d%d", &n, &m, &s);
  rep(i, m) {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    G[a].pb((edge){b, c});
  }
  fill(d, d + n, INF);
  dijkstra(s);
  rep(i, n) {
    if (d[i] == INF) {
      cout << "INF\n";
    } else {
      cout << d[i] << "\n";
    }
  }
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
#define ll long long
#define INF 1000000005
#define MOD 1000000007
#define EPS 1e-10
#define rep(i, n) for (int i = 0; i < (int)(n); ++i)
#define rrep(i, n) for (int i = (int)(n)-1; i >= 0; --i)
#define srep(i, s, t) for (int i = (int)(s); i < (int)(t); ++i)
#define each(a, b) for (auto(a) : (b))
#define all(v) (v).begin(), (v).end()
#define len(v) (int)(v).size()
#define zip(v) sort(all(v)), v.erase(unique(all(v)), v.end())
#define cmx(x, y) x = max(x, y)
#define cmn(x, y) x = min(x, y)
#define fi first
#define se second
#define pb push_back
#define show(x) cout << #x << " = " << (x) << endl
#define spair(p) cout << #p << ": " << p.fi << " " << p.se << endl
#define svec(v)                                                                \
  cout << #v << ":";                                                           \
  rep(kbrni, v.size()) cout << " " << v[kbrni];                                \
  cout << endl
#define sset(s)                                                                \
  cout << #s << ":";                                                           \
  each(kbrni, s) cout << " " << kbrni;                                         \
  cout << endl
#define smap(m)                                                                \
  cout << #m << ":";                                                           \
  each(kbrni, m) cout << " {" << kbrni.first << ":" << kbrni.second << "}";    \
  cout << endl

using namespace std;

typedef pair<int, int> P;
typedef pair<ll, ll> pll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<ll> vl;
typedef vector<double> vd;
typedef vector<P> vp;
typedef vector<string> vs;

const int MAX_N = 100005;

template <typename T> class Heap {
public:
  struct node {
    node *l;
    node *r;
    T val;
    node(T t) : l(nullptr), r(nullptr), val(t) {}
  };
  node *root;
  Heap() : root(nullptr) {}
  node *meld(node *a, node *b) {
    if (!a)
      return b;
    if (!b)
      return a;
    if (a->val > b->val)
      swap(a, b);
    a->r = meld(a->r, b);
    swap(a->l, a->r);
    return a;
  }
  void push(T val) {
    node *p = new node(val);
    root = meld(root, p);
  }
  T top() { return root->val; }
  void pop() {
    node *p = root;
    root = meld(root->r, root->l);
    delete p;
  }
};

struct edge {
  int to, cost;
};

int d[MAX_N];
vector<edge> G[MAX_N];

void dijkstra(int s) {
  Heap<P> que;
  d[s] = 0;
  que.push(P(0, s));
  while (que.root) {
    P p = que.top();
    que.pop();
    int v = p.second;
    if (d[v] < p.first)
      continue;
    for (auto w : G[v]) {
      if (d[w.to] > d[v] + w.cost) {
        d[w.to] = d[v] + w.cost;
        que.push(P(d[w.to], w.to));
      }
    }
  }
}

int main() {
  int n, m, s;
  scanf("%d%d%d", &n, &m, &s);
  rep(i, m) {
    int a, b, c;
    scanf("%d%d%d", &a, &b, &c);
    G[a].pb((edge){b, c});
  }
  fill(d, d + n, INF);
  dijkstra(s);
  rep(i, n) {
    if (d[i] == INF) {
      cout << "INF\n";
    } else {
      cout << d[i] << "\n";
    }
  }
  return 0;
}