Submission #684501

#	Time	Username	Problem	Language	Result	Execution time	Memory
684501		JooDdae	Commuter Pass (JOI18_commuter_pass)	C++17	15 / 100	305 ms	23736 KiB

commuter_pass

#include <bits/stdc++.h>
using namespace std;
using ll = long long;

const ll INF = 1e18;

int n, m, S, T, U, V;
vector<array<int, 2>> v[100100];

ll d[100100];
bool chk[100100];
priority_queue<array<ll, 2>> pq;

ll d2[100100][4];
priority_queue<array<ll, 3>> pq2;

void dfs(int u) {
    assert(!chk[u]);
    chk[u] = 1;
    for(auto [x, y] : v[u]) if(d[u]-y == d[x]) dfs(x);
}

int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> m >> S >> T >> U >> V;
    for(int i=1;i<=m;i++) {
        int a, b, c; cin >> a >> b >> c;
        v[a].push_back({b, c}), v[b].push_back({a, c});
    }
    fill(d+1, d+1+n, INF);
    d[S] = 0, pq.push({0, S});
    while(!pq.empty()) {
        auto [c, u] = pq.top(); pq.pop();
        if(-c > d[u]) continue;
        for(auto [x, y] : v[u]) if(y-c < d[x]) d[x] = y-c, pq.push({c-y, x});
    }
    dfs(T);

    for(int i=1;i<=n;i++) d2[i][0] = d2[i][1] = d2[i][2] = d2[i][3] = INF;

    d2[U][0] = 0, pq2.push({0, U, 0});
    while(!pq2.empty()) {
        auto [c, u, t] = pq2.top(); pq2.pop();
        if(-c > d2[u][t]) continue;
        if(u == V) return cout << -c, 0;
        if(t < 3 && chk[u]) for(auto [x, y] : v[u]) if(chk[x] && abs(d[x]-d[u]) == y){
            if(t == 1 && d[x] > d[u]) continue;
            if(t == 2 && d[x] < d[u]) continue;
            ll T = d[x] > d[u] ? 2 : 1;
            if(-c < d2[x][T]) d2[x][T] = -c, pq2.push({c, x, T});
        }
        for(auto [x, y] : v[u]) {
            ll D = y-c, T = t ? 3 : 0;
            if(D < d2[x][T]) d2[x][T] = D, pq2.push({-D, x, T});
        }
    }
}

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