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39 lines
944 B
C++
39 lines
944 B
C++
#include <bits/stdc++.h>
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using namespace std;
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int n, m, s, t, u, v, w, dist[2505];
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vector<pair<int, int>> g[2505];
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bool st[2505];
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void dijkstra() {
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memset(dist, 0x3f, sizeof(dist));
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dist[s] = 0;
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priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
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q.push(make_pair(0, s));
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while (!q.empty()) {
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auto t = q.top();
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q.pop();
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if (st[t.second]) continue;
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for (auto i : g[t.second]) {
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if (dist[i.first] > t.first + i.second) {
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dist[i.first] = t.first + i.second;
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q.push(make_pair(dist[i.first], i.first));
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}
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}
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st[t.second] = true;
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}
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}
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int main() {
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cin >> n >> m >> s >> t;
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for (int i = 1; i <= m; i++) {
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cin >> u >> v >> w;
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g[u].push_back(make_pair(v, w));
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g[v].push_back(make_pair(u, w));
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}
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dijkstra();
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cout << dist[t] << endl;
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return 0;
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}
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