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https://git.sb/baoshuo/OI-codes.git
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59 lines
1011 B
C++
59 lines
1011 B
C++
#include <iostream>
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#include <algorithm>
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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 = 3e5 + 5;
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int n1, n2, m, dist1[N], dist2[N];
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bool vis[N];
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std::vector<int> g[N];
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void bfs(int s, int* dist) {
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std::queue<int> q;
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q.emplace(s);
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vis[s] = true;
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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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for (int v : g[u]) {
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if (vis[v]) continue;
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vis[v] = true;
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dist[v] = dist[u] + 1;
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q.emplace(v);
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}
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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.tie(nullptr);
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cin >> n1 >> n2 >> m;
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for (int i = 1, u, v; i <= m; i++) {
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cin >> u >> v;
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g[u].emplace_back(v);
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g[v].emplace_back(u);
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}
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bfs(1, dist1);
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bfs(n1 + n2, dist2);
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cout << *std::max_element(dist1 + 1, dist1 + 1 + n1)
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+ *std::max_element(dist2 + n1 + 1, dist2 + n1 + n2 + 1) + 1
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<< endl;
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return 0;
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}
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