哪裡有卦，哪裡就有源(TOJ 1101)
題目連結
明顯的二分圖水題喔～
用 dfs 把經過的點標出黑白，過程中如果遇到問題就表示非二分圖了
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| #include <bits/stdc++.h>
#define ios ios::sync_with_stdio(0),cin.tie(0)
#define int long long
using namespace std;
int n;
bool visit[100005],color[100005];
vector<int> edge[100005];
bool dfs(int id, bool col){
visit[id] = 1;
color[id] = col;
int len = edge[id].size();
for(int i=0;i<len;i++){
int temp = edge[id][i];
if(visit[temp]){
if(color[temp]==col)return 0;
else continue;
}
if(!dfs(temp, !col))return 0;
}
return 1;
}
signed main(){
ios;
while(cin>>n && n){
int m;cin>>m;
for(int i=0;i<n;i++)edge[i].clear();
memset(visit, 0, sizeof(visit));
memset(color, 0, sizeof(color));
while(m--){
int a,b;cin>>a>>b;
edge[a].push_back(b);
edge[b].push_back(a);
}
bool f = 1;
for(int i=0;i<n;i++){
if(!visit[i]){
if(!dfs(i, 0)){
f = 0;
break;
}
}
}
if(f)cout<<"NORMAL."<<endl;
else cout<<"RAINBOW."<<endl;
}
}
|