Problem p01911 (C++)

Buggy submission (status: Runtime Error):
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define rep(i, n) for (int(i) = 0; (i) < (int)(n); ++(i))
#define each(itr, c)                                                           \
  for (__typeof(c.begin()) itr = c.begin(); itr != c.end(); ++itr)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define fi first
#define se second

typedef pair<int, int> pi;

const int V = 100000;
const int N = 202020;
const int INF = 123456789;

set<int> TIMESET[V];
map<pi, int> v_to_id;

struct edge {
  int to, cost;
};
vector<edge> G[N];
int dist[N];

int main() {
  int n, m, s, g;
  scanf(" %d %d %d %d", &n, &m, &s, &g);
  --s;
  --g;

  TIMESET[s].insert(0);
  v_to_id[pi(s, 0)] = 0;

  int idx = 1;

  rep(i, m) {
    int u, v, t, c;
    scanf(" %d %d %d %d", &u, &v, &t, &c);
    --u;
    --v;

    TIMESET[u].insert(t);
    TIMESET[v].insert(t + c);

    if (v_to_id.find(pi(u, t)) == v_to_id.end())
      v_to_id[pi(u, t)] = idx++;
    if (v_to_id.find(pi(v, t + c)) == v_to_id.end())
      v_to_id[pi(v, t + c)] = idx++;

    int S = v_to_id[pi(u, t)], T = v_to_id[pi(v, t + c)];
    G[S].pb(edge{T, 0});
  }

  rep(i, n) {
    int SZ = TIMESET[i].size();

    auto itr = TIMESET[i].begin();
    rep(j, SZ - 1) {
      auto nx = itr;
      ++nx;

      int d = *nx - *itr;
      int S = v_to_id[pi(i, *itr)], T = v_to_id[pi(i, *nx)];
      G[S].pb(edge{T, d});

      ++itr;
    }
  }

  priority_queue<pi, vector<pi>, greater<pi>> pq;
  pq.push(pi(0, 0));
  fill(dist, dist + N, INF);
  dist[0] = 0;
  while (!pq.empty()) {
    pi p = pq.top();
    pq.pop();
    int v = p.se;
    if (dist[v] < p.fi)
      continue;
    for (edge &e : G[v]) {
      if (dist[e.to] > dist[v] + e.cost) {
        dist[e.to] = dist[v] + e.cost;
        pq.push(pi(dist[e.to], e.to));
      }
    }
  }

  int ans = INF;
  for (const auto &x : TIMESET[g]) {
    int S = v_to_id[pi(g, x)];
    ans = min(ans, dist[S]);
  }
  printf("%d\n", ans);
  return 0;
}

Fixed submission:
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
#define rep(i, n) for (int(i) = 0; (i) < (int)(n); ++(i))
#define each(itr, c)                                                           \
  for (__typeof(c.begin()) itr = c.begin(); itr != c.end(); ++itr)
#define all(x) (x).begin(), (x).end()
#define pb push_back
#define fi first
#define se second

typedef pair<int, int> pi;

const int V = 100000;
const int N = 404040;
const int INF = 123456789;

set<int> TIMESET[V];
map<pi, int> v_to_id;

struct edge {
  int to, cost;
};
vector<edge> G[N];
int dist[N];

int main() {
  int n, m, s, g;
  scanf(" %d %d %d %d", &n, &m, &s, &g);
  --s;
  --g;

  TIMESET[s].insert(0);
  v_to_id[pi(s, 0)] = 0;

  int idx = 1;

  rep(i, m) {
    int u, v, t, c;
    scanf(" %d %d %d %d", &u, &v, &t, &c);
    --u;
    --v;

    TIMESET[u].insert(t);
    TIMESET[v].insert(t + c);

    if (v_to_id.find(pi(u, t)) == v_to_id.end())
      v_to_id[pi(u, t)] = idx++;
    if (v_to_id.find(pi(v, t + c)) == v_to_id.end())
      v_to_id[pi(v, t + c)] = idx++;

    int S = v_to_id[pi(u, t)], T = v_to_id[pi(v, t + c)];
    G[S].pb(edge{T, 0});
  }

  rep(i, n) {
    int SZ = TIMESET[i].size();

    auto itr = TIMESET[i].begin();
    rep(j, SZ - 1) {
      auto nx = itr;
      ++nx;

      int d = *nx - *itr;
      int S = v_to_id[pi(i, *itr)], T = v_to_id[pi(i, *nx)];
      G[S].pb(edge{T, d});

      ++itr;
    }
  }

  priority_queue<pi, vector<pi>, greater<pi>> pq;
  pq.push(pi(0, 0));
  fill(dist, dist + N, INF);
  dist[0] = 0;
  while (!pq.empty()) {
    pi p = pq.top();
    pq.pop();
    int v = p.se;
    if (dist[v] < p.fi)
      continue;
    for (edge &e : G[v]) {
      if (dist[e.to] > dist[v] + e.cost) {
        dist[e.to] = dist[v] + e.cost;
        pq.push(pi(dist[e.to], e.to));
      }
    }
  }

  int ans = INF;
  for (const auto &x : TIMESET[g]) {
    int S = v_to_id[pi(g, x)];
    ans = min(ans, dist[S]);
  }
  printf("%d\n", ans);
  return 0;
}