Problem p02361 (C++)

Buggy submission (status: Runtime Error):
#include <algorithm>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i, j) for (int i = 0; i < (int)(j); ++i)
#define FOR(i, j, k) for (int i = (int)(j); i < (int)(k); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define REVERSE(v) reverse((v).begin(), (v).end())
// typedef complex<double> P;
typedef pair<int, int> P;
const int MAX_V = 100010;
const int INF = 1e9 + 7;

int dijkstra(const vector<vector<P>> &cost, int s, int t, int V) {
  priority_queue<P, vector<P>, greater<P>> open;
  open.push(P(s, 0));
  int closed[MAX_V];
  REP(i, V) closed[i] = INF;
  while (!open.empty()) {
    P tmp = open.top();
    open.pop();
    int now = tmp.first, c = tmp.second;
    if (closed[now] < c)
      continue;
    closed[now] = c;
    REP(i, cost[now].size()) {
      int next = cost[now][i].first, nc = cost[now][i].second;
      if (nc == INF || c + nc >= closed[next])
        continue;
      closed[next] = c + nc;
      open.push(P(next, closed[next]));
    }
  }
  REP(i, V) {
    if (closed[i] == INF)
      cout << "INF" << endl;
    else
      cout << closed[i] << endl;
  }
  return closed[t];
}

int main() {
  int V, E, r;
  cin >> V >> E >> r;
  vector<vector<P>> cost(V);
  REP(i, E) {
    int f, t, c;
    cin >> f >> t >> c;
    cost[f].push_back(P(t, c));
  }
  REP(i, E) {
    if ((int)cost[i].size() <= 0)
      continue;
    SORT(cost[i]);
    vector<P> tmp;
    int now = cost[i][0].first;
    tmp.push_back(cost[i][0]);
    FOR(j, 1, cost[i].size()) {
      if (now == cost[i][j].first)
        continue;
      now = cost[i][j].first;
      tmp.push_back(cost[i][j]);
    }
    cost[i] = tmp;
  }
  dijkstra(cost, r, -1, V);
  return 0;
}

Fixed submission:
#include <algorithm>
#include <cctype>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <deque>
#include <iostream>
#include <limits>
#include <list>
#include <map>
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <string>
#include <vector>
using namespace std;
#define REP(i, j) for (int i = 0; i < (int)(j); ++i)
#define FOR(i, j, k) for (int i = (int)(j); i < (int)(k); ++i)
#define SORT(v) sort((v).begin(), (v).end())
#define REVERSE(v) reverse((v).begin(), (v).end())
// typedef complex<double> P;
typedef pair<int, int> P;
const int MAX_V = 100010;
const int INF = 1e9 + 7;

int dijkstra(const vector<vector<P>> &cost, int s, int t, int V) {
  priority_queue<P, vector<P>, greater<P>> open;
  open.push(P(s, 0));
  int closed[MAX_V];
  REP(i, V) closed[i] = INF;
  while (!open.empty()) {
    P tmp = open.top();
    open.pop();
    int now = tmp.first, c = tmp.second;
    if (closed[now] < c)
      continue;
    closed[now] = c;
    REP(i, cost[now].size()) {
      int next = cost[now][i].first, nc = cost[now][i].second;
      if (nc == INF || c + nc >= closed[next])
        continue;
      closed[next] = c + nc;
      open.push(P(next, closed[next]));
    }
  }
  REP(i, V) {
    if (closed[i] == INF)
      cout << "INF" << endl;
    else
      cout << closed[i] << endl;
  }
  return closed[t];
}

int main() {
  int V, E, r;
  cin >> V >> E >> r;
  vector<vector<P>> cost(V);
  REP(i, E) {
    int f, t, c;
    cin >> f >> t >> c;
    cost[f].push_back(P(t, c));
  }
  // REP(i, E){
  //   if((int)cost[i].size() <= 0) continue;
  //   SORT(cost[i]);
  //   vector<P> tmp;
  //   int now = cost[i][0].first;
  //   tmp.push_back(cost[i][0]);
  //   FOR(j, 1, cost[i].size()){
  //     if(now == cost[i][j].first) continue;
  //     now = cost[i][j].first;
  //     tmp.push_back(cost[i][j]);
  //   }
  //   cost[i] = tmp;
  // }
  dijkstra(cost, r, -1, V);
  return 0;
}