제출 #833714

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
833714		vjudge1	Commuter Pass (JOI18_commuter_pass)	C++17	0 / 100	10 ms	13268 KiB

commuter_pass

#include <bits/stdc++.h>
#define int long long
#define pii pair<int, int>

using namespace std;

const int N = 1e5 + 2;
vector<pair<int, int>>adj1[N], adj2[N];
vector<tuple<int, int, int>>edge;
int p[N], dist[N];

int32_t main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    int n, m; cin >> n >> m;
    int s, t; cin >> s >> t;
    int x, y; cin >> x >> y;

    for(int i = 1; i <= N; i++){
        dist[i] = 1e18;
        p[i] = i;
    }

    while(m--){
        int u, v, w; cin >> u >> v >> w;
        edge.emplace_back(u, v, w);
        adj1[u].emplace_back(v, w);
        adj1[v].emplace_back(u, w);
    }

    priority_queue<pii, vector<pii>, greater<pii>>pq;
    pq.emplace(0LL, s);

    while(!pq.empty()){
        auto [curW, u] = pq.top(); pq.pop();
        for(auto &[v, w]: adj1[u]){
            if(dist[v] <= curW + w) continue;
            dist[v] = curW + w;
            p[v] = u;
            pq.emplace(dist[v], v);
        }
    }

    set<pair<int, int>>st;
    int cur = t;
    while(cur != s){
        st.insert({cur, p[cur]});
        st.insert({p[cur], cur});

        cur = p[cur];
    }   

    for(auto &[u, v, w]: edge){
        if(st.count({u, v})) w = 0;
        adj2[u].emplace_back(v, w);
        adj2[v].emplace_back(u, w);
    }

    for(int i = 1; i <= n; i++) dist[i] = 1e18;

    pq.emplace(0LL, x);
    dist[x] = 0;

    while(!pq.empty()){
        auto [curW, u] = pq.top(); pq.pop();
        for(auto &[v, w]: adj2[u]){
            if(dist[v] <= curW + w) continue;
            dist[v] = curW + w;
            p[v] = u;
            pq.emplace(dist[v], v);
        }
    }

    cout << dist[y] << '\n';

    return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

commuter_pass.cpp: In function 'int32_t main()':
commuter_pass.cpp:19:17: warning: iteration 100001 invokes undefined behavior [-Waggressive-loop-optimizations]
   19 |         dist[i] = 1e18;
      |         ~~~~~~~~^~~~~~
commuter_pass.cpp:18:22: note: within this loop
   18 |     for(int i = 1; i <= N; i++){
      |                    ~~^~~~

• Subtask 1: 0 / 16
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 45