Submission #1087635

#	Time	Username	Problem	Language	Result	Execution time	Memory
1087635		FubuGold	Commuter Pass (JOI18_commuter_pass)	C++14	0 / 100	2070 ms	234420 KiB

commuter_pass

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

using namespace std;

const int maxn = 1e5 + 2;
const int inf = LLONG_MAX / 5;

int n,m,ans=inf;
int D,S,T,U,V;
vector<pii> a[maxn];
vector<int> b[maxn];
int d[5][maxn], tq[maxn], tu[maxn], tv[maxn];
multiset<int> su,sv;

void BRUTE(int u, int cnt) {
    for (int i = 1; i <= n; i++) d[cnt][i] = inf;
    d[cnt][u] = 0;
    for (int i = 1; i <= n; i++) {
        for (int u = 1; u <= n; u++) {
            for (pii tmp: a[u]) {
                int v,val; tie(v,val) = tmp;
                d[cnt][v] = min(d[cnt][v], d[cnt][u] + val);
            }
        }
    }
}

void dfs(int u) {
    su.insert(d[2][u]);
    sv.insert(d[3][u]);
//    cerr << "> "<< u << " " << T << endl;
    if (u == T) {
        ans = min(ans, *su.begin()+ *sv.begin());
        return;
    }
    for (pii tmp : a[u]) {
        int v = tmp.first;
//        cerr << "? " << v << " and " << D << endl;
        if ( d[0][u] + tmp.second + d[1][v] == D ) {
            dfs(v);
        }
    }
    su.erase(su.find(d[2][u]));
    sv.erase(sv.find(d[3][u]));
}


signed main() {
//    freopen("BUS.INP", "r", stdin);
//    freopen("BUS.ANS", "w", stdout);
    cin.tie(0) -> sync_with_stdio(0);
    cin >> n >> m;
    cin >> S >> T >> U >> V;
    for (int i= 1; i <= m; i++) {
        int x,y,h; cin >> x >> y >> h;
        a[x].push_back({y,h});
        a[y].push_back({x,h});
    }
    BRUTE(S,0);
    BRUTE(T,1);
    BRUTE(U,2);
    BRUTE(V,3);
    D = d[0][T];
//    for (int i= 1; i <= n; i++) cerr << S << " dis: " << i << " = " << d[0][i] << endl;
    dfs(S);
    cout << ans;
}

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