Submission #1026968

#TimeUsernameProblemLanguageResultExecution timeMemory
1026968vjudge1Pipes (CEOI15_pipes)C++17
Compilation error
0 ms0 KiB
#include <bits/stdc++.h> #define ll long long using namespace std; const int N = 1e5; vector < int > adj[N + 2]; struct dsu{ int par[N + 2]; int find_par(int &u){ if(par[u] < 0)return u; par[u] = find_par(par[u]); return par[u]; } bool union_set(int u , int v){ u = find_par(u); v = find_par(v); if(u != v){ if(par[u] > par[v])swap(u , v); par[u] += par[v]; par[v] = u; return true; } return false; } } par1 , par2; int timer = 0; void dfs(int &u , int &p){ par1.par[u] = par2.par[u] = ++timer; for(int v:adj[u]){ if(v == p) continue; if(!par2.par[v]){ dfs(v , u); par1.par[u] = min(par1.par[u] , par1.par[v]); if(par1.par[v] == par2.par[v]) cout << u << " " << v <<'\n'; } else par1.par[u] = min(par1.par[u] , par2.par[v]); } } void solve() { int n , m; cin >> n >> m; memset(par1.par , -1 , sizeof(par1.par)); memset(par2.par , -1 , sizeof(par2.par)); for(int i = 1; i <= m ;i ++){ int u , v; cin >> u >> v; if(par1.union_set(u , v)){ adj[u].push_back(v); adj[v].push_back(u); } else if(par2.union_set(u , v)){ adj[u].push_back(v); adj[v].push_back(u); } } memset(par1.par , 0 , sizeof(par1.par)); memset(par2.par , 0 , sizeof(par2.par)); for(int i = 1; i <= n ; i++){ if(!par2.par[i])dfs(i , 0); } } signed main() { ios::sync_with_stdio(0), cin.tie(0); #define _ "maxseq." if (fopen(_ "inp", "r")) { freopen(_ "inp", "r", stdin); freopen(_ "out", "w", stdout); } solve(); }

Compilation message (stderr)

pipes.cpp: In function 'void solve()':
pipes.cpp:61:33: error: cannot bind non-const lvalue reference of type 'int&' to an rvalue of type 'int'
   61 |         if(!par2.par[i])dfs(i , 0);
      |                                 ^
pipes.cpp:28:24: note:   initializing argument 2 of 'void dfs(int&, int&)'
   28 | void dfs(int &u , int &p){
      |                   ~~~~~^
pipes.cpp: In function 'int main()':
pipes.cpp:71:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   71 |         freopen(_ "inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
pipes.cpp:72:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   72 |         freopen(_ "out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~