mirror of
https://git.sb/baoshuo/OI-codes.git
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101 lines
1.8 KiB
C++
101 lines
1.8 KiB
C++
#include <algorithm>
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#include <fstream>
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#include <queue>
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#include <unordered_map>
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#include <vector>
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std::ifstream cin("travel.in");
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std::ofstream cout("travel.out");
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const char endl = '\n';
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const int N = 5005;
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int n, m, s, t, in[N];
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bool vis[N];
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std::vector<int> c, g[N];
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std::unordered_map<int, int> map[N];
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void cycle() {
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std::queue<int> q;
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for (int i = 1; i <= n; i++) {
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if (in[i] == 1) q.push(i);
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}
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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 (in[v] > 1) {
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if (--in[v] == 1) q.push(v);
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}
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}
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}
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}
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void dfs(int u, int fa, std::vector<int> &res) {
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if (vis[u]) return;
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vis[u] = true;
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res.push_back(u);
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for (int v : g[u]) {
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if (v == fa || u == s && v == t || v == s && u == t) continue;
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dfs(v, u, res);
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}
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vis[u] = false;
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}
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int main() {
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cin >> n >> 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].push_back(v);
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g[v].push_back(u);
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in[u]++, in[v]++;
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map[u][v] = map[v][u] = true;
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}
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cycle();
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for (int i = 1; i <= n; i++) {
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std::sort(g[i].begin(), g[i].end());
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if (in[i] >= 2) c.push_back(i);
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}
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std::vector<int> ans;
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if (n == m) {
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ans = std::vector<int>(n, n);
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for (int i = 0; i < c.size(); i++) {
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for (int j = i + 1; j < c.size(); j++) {
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s = c[i], t = c[j];
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if (!map[s][t]) continue;
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std::vector<int> res;
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dfs(1, 0, res);
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ans = std::min(ans, res);
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}
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}
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} else {
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dfs(1, 0, ans);
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}
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for (int &ans : ans) {
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cout << ans << ' ';
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}
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cout << endl;
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return 0;
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}
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