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35 lines
694 B
C++
35 lines
694 B
C++
#include <bits/stdc++.h>
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using namespace std;
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struct node {
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int u, v, w;
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} g[10005];
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int n, m, k, dist[505], backup[505];
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void bellman_ford() {
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memset(dist, 0x3f, sizeof(dist));
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dist[1] = 0;
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for (int i = 1; i <= k; i++) {
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memcpy(backup, dist, sizeof(dist));
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for (int j = 1; j <= m; j++) {
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dist[g[j].v] = min(dist[g[j].v], backup[g[j].u] + g[j].w);
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}
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}
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}
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int main() {
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cin >> n >> m >> k;
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for (int i = 1; i <= m; i++) {
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cin >> g[i].u >> g[i].v >> g[i].w;
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}
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bellman_ford();
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if (dist[n] > 0x1f1f1f1f) {
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cout << "impossible" << endl;
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} else {
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cout << dist[n] << endl;
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}
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return 0;
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}
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