uva 10004

 

Uva 10004 Bicoloring

用了一个深搜加路径判断，出现环且结点数为奇数时不符合

 

#include <iostream>using namespace std;int mat[210][210],vis[210],n,t,last[210];bool dfs(int u,int path){vis[u]=-1;int v;for(v=0;v<n;v++)if(last[u]==v ||vis[v]==1)continue;else if(mat[u][v]){path++;if(vis[v]<0){path--;if(path%2)return false;elsereturn true;}else{last[v]=u;if(!dfs(v,path))return false;}}vis[u]=1;return true;}int main(){int t,i,r,c,path;bool p;while(cin>>n){memset(mat,0,sizeof(mat));memset(last,-1,sizeof(last));memset(vis,0,sizeof(vis));p=true;if(n==0)break;cin>>t;for(i=0;i<t;i++){cin>>r>>c;mat[r][c]=1;mat[c][r]=1;}for(i=0;i<n && p;i++)if(vis[i]==0){path=1;p=dfs(i,path);}if(p)cout<<"BICOLORABLE."<<endl;elsecout<<"NOT BICOLORABLE."<<endl;}return 0;}