Submission #729362

#	Time	Username	Problem	Language	Result	Execution time	Memory
729362		Pring	Commuter Pass (JOI18_commuter_pass)	C++14	15 / 100	275 ms	23052 KiB

commuter_pass

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

#define int long long
typedef pair<int, int> pii;

const int MXN = 100005;
int n, m, s, t, u, v, father[MXN], du[MXN], dv[MXN], uu = LLONG_MAX, vv = LLONG_MAX;
vector<pii> edge[MXN];
vector<int> path;
bitset<MXN> b;

void GET_PATH() {
    b.reset();
    priority_queue<pair<int, pii>, vector<pair<int, pii>>, greater<pair<int, pii>>> pq;
    pq.push({0, {0, s}});
    while (pq.size()) {
        pair<int, pii> now = pq.top();
        pq.pop();
        if (b[now.second.second]) continue;
        b[now.second.second] = true;
        father[now.second.second] = now.second.first;
        for (auto &i : edge[now.second.second]) {
            if (b[i.first]) continue;
            pq.push({now.first + i.second, {now.second.second, i.first}});
        }
    }
    int now = t;
    path.push_back(now);
    while (now != s) {
        now = father[now];
        path.push_back(now);
    }
}

void DIJKSTRA(int start, int *arr) {
    b.reset();
    priority_queue<pii, vector<pii>, greater<pii>> pq;
    pq.push({0, start});
    while (pq.size()) {
        pii now = pq.top();
        pq.pop();
        if (b[now.second]) continue;
        b[now.second] = true;
        arr[now.second] = now.first;
        for (auto &i : edge[now.second]) {
            if (b[i.first]) continue;
            pq.push({now.first + i.second, i.first});
        }
    }
}

int32_t main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int x, y, z;
    cin >> n >> m >> s >> t >> u >> v;
    for (int i = 0; i < m; i++) {
        cin >> x >> y >> z;
        edge[x].push_back({y, z});
        edge[y].push_back({x, z});
    }
    GET_PATH();
    DIJKSTRA(u, du);
    DIJKSTRA(v, dv);
    for (auto &i : path) {
        uu = min(uu, du[i]);
        vv = min(vv, dv[i]);
    }
    cout << min(du[v], uu + vv) << endl;
    return 0;
}

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