https://vjudge.net/problem/HihoCoder-1121
#include<cstdio>
#include<cstring>
#include<vector>
#include<iostream>
#define N 10000010
using namespace std;
vector<int>E[N];
int v[N],i,j,k,n,tt,s,t,m,f;
bool dfs(int x) {
for (int i=0; i<E[x].size(); i++) {
int t=E[x][i];
if (v[x]==v[t]) return 0;
if (v[t]==0) {
v[t]=-v[x];
if (!dfs(t)) return 0;
}
}
return 1;
}
int main() {
scanf("%d",&tt);
while (tt--) {
scanf("%d%d",&n,&m);
for (i=1;i<=n;i++){
E[i].clear();
}
while (m--) {
scanf("%d%d",&s,&t);
E[s].push_back(t);
E[t].push_back(s);
}
memset(v,0,sizeof(v));
f=0;
for (i=1; i<=n; i++) {
if (v[i]==0) {
v[i]=1;
if (!dfs(i)) {
f=1;
printf("Wrong\n");
break;
}
}
}
if (f==0) printf("Correct\n");
}
}