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https://git.sb/baoshuo/OI-codes.git
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50 lines
1.0 KiB
C++
50 lines
1.0 KiB
C++
#include <iostream>
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#include <cstring>
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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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#define endl '\n'
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int n, x, dist[105];
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std::vector<std::pair<int, int>> g[105];
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bool vis[105];
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void spfa(int s) {
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memset(dist, 0x3f, sizeof(dist));
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std::queue<int> q;
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q.push(s);
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vis[s] = true;
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dist[s] = 1;
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while (!q.empty()) {
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int u = q.front();
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q.pop();
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vis[u] = false;
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for (auto e : g[u]) {
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int v = e.first,
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w = e.second;
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if (dist[v] > std::max(1, (dist[u] + w + 1) / 2)) {
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dist[v] = std::max(1, (dist[u] + w + 1) / 2);
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if (!vis[v]) {
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q.push(v);
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vis[v] = true;
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}
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}
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}
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}
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}
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int main() {
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cin >> n;
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for (int i = 1; i <= n; i++) {
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for (int j = 1; j <= n; j++) {
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cin >> x;
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if (x) g[j].push_back(std::make_pair(i, -x));
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}
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}
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spfa(n);
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cout << dist[1] << endl;
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return 0;
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}
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