Submission #959305

#TimeUsernameProblemLanguageResultExecution timeMemory
959305Cyber_WolfPipes (CEOI15_pipes)C++17
60 / 100
997 ms61076 KiB
#include <bits/stdc++.h> using namespace std; const int N = 1e5+5; vector<int> adj[N]; int tin[N], par[N][2], low[N]; int get1(int src) { return par[src][0] = (src == par[src][0] ? src : get1(par[src][0])); } int get2(int src) { return par[src][1] = (src == par[src][1] ? src : get2(par[src][1])); } int n, m, tmp, pa = -1; void dfs(int src) { bool a = false; tin[src] = low[src] = ++tmp; for(auto it : adj[src]) { if(it == pa && !a) { a = true; continue; } if(tin[it]) { low[src] = min(low[src], tin[it]); continue; } swap(pa, src); dfs(it); swap(pa, src); low[src] = min(low[src], low[it]); if(low[it] > tin[src]) { printf("%d %d\n", src, it); } } return ; } int main() { ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0); scanf("%d%d", &n, &m); for(int i = 1; i <= n; i++) par[i][0] = par[i][1] = i; int u, v, pU, pV; while(m--) { scanf("%d%d", &u, &v); pU = get1(u), pV = get1(v); if(pU != pV) { par[pU][0] = pV; adj[u].push_back(v), adj[v].push_back(u); } else{ pU = get2(u), pV = get2(v); if(pU != pV) { par[pU][1] = pV; adj[u].push_back(v), adj[v].push_back(u); } } } for(int i = 1; i <= n; i++) { if(!tin[i]) dfs(i); } return 0; }

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:55:7: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |  scanf("%d%d", &n, &m);
      |  ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:60:8: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |   scanf("%d%d", &u, &v);
      |   ~~~~~^~~~~~~~~~~~~~~~
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