47 lines
1.3 KiB
C++
47 lines
1.3 KiB
C++
// 教材例 10-1 / 洛谷 P3371：非负边权单源最短路。
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// 输入 n m s，随后 m 行 u v w；有向边，可含重边和零权边。
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#include <iostream>
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#include <vector>
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#include <queue>
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#include <utility>
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#include <functional>
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using namespace std;
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using ll = long long;
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using State = pair<ll, int>;
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struct Edge { int to; ll w; };
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int main() {
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ios::sync_with_stdio(false);
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cin.tie(nullptr);
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int n, m, s;
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if (!(cin >> n >> m >> s)) return 0;
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vector<vector<Edge>> g(n + 1);
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for (int i = 0; i < m; ++i) {
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int u, v; ll w;
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cin >> u >> v >> w;
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g[u].push_back({v, w});
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}
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const ll INF = (1LL << 60);
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vector<ll> dis(n + 1, INF);
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priority_queue<State, vector<State>, greater<State>> q;
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dis[s] = 0;
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q.push({0, s});
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while (!q.empty()) {
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State cur = q.top();
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q.pop();
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ll d = cur.first;
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int u = cur.second;
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if (d != dis[u]) continue; // 旧记录不再扫描出边
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for (const auto &e : g[u]) {
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int v = e.to;
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ll nd = d + e.w;
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if (nd < dis[v]) {
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dis[v] = nd;
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q.push({nd, v});
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}
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}
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}
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for (int i = 1; i <= n; ++i)
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cout << (dis[i] == INF ? 2147483647LL : dis[i])
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<< (i == n ? '\n' : ' ');
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}
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