mirror of
https://git.sb/baoshuo/OI-codes.git
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74 lines
1.6 KiB
C++
74 lines
1.6 KiB
C++
#include <cstring>
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#include <iostream>
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#include <queue>
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#include <vector>
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using std::cin;
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using std::cout;
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const char endl = '\n';
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const int N = 55;
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int n, m, k, dist[N << 6];
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std::vector<std::pair<int, int>> g[N << 6];
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bool vis[N << 6];
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void dijkstra() {
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memset(dist, 0x3f, sizeof(dist));
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std::priority_queue<std::pair<int, int>, std::vector<std::pair<int, int>>, std::greater<std::pair<int, int>>> q;
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q.push(std::make_pair(0, 1));
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dist[1] = 0;
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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 (vis[t.second]) continue;
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for (auto e : g[t.second]) {
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int v = e.first,
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w = e.second;
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if (dist[v] > t.first + w) {
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dist[v] = t.first + w;
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q.push(std::make_pair(dist[v], v));
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}
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}
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vis[t.second] = true;
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}
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}
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int main() {
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std::ios::sync_with_stdio(false);
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cin >> n >> m >> k;
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for (int i = 1, u, v, w; i <= m; i++) {
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cin >> u >> v >> w;
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g[u].push_back(std::make_pair(v, w));
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g[v].push_back(std::make_pair(u, w));
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for (int j = 1; j <= k; j++) {
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g[u + (j - 1) * n].push_back(std::make_pair(v + j * n, w >> 1));
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g[v + (j - 1) * n].push_back(std::make_pair(u + j * n, w >> 1));
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g[u + j * n].push_back(std::make_pair(v + j * n, w));
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g[v + j * n].push_back(std::make_pair(u + j * n, w));
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}
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}
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for (int i = 0; i <= k; i++) {
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g[i * n].push_back(std::make_pair(i * n + n, 0));
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}
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dijkstra();
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cout << dist[n * k + n] << endl;
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return 0;
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}
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