NYOJ--20--搜索（dfs）--吝啬的国度

题意，N座城市有N-1条路，目的是找到哪个城市可以到目的城市

//NYOJ--search--吝啬的国度
#include<iostream>
#include<vector>
#include<cstring>
using namespace std;
vector<int> city[100005];
int road[100004];
int N,S;
void dfs(int);
int main(){
    
//    freopen("in.txt","r",stdin);
//    freopen("out.txt","a+",stdout);
    int M;cin>>M;
    while(M--){
        
        memset(city,0,sizeof(city));
        memset(road,0,sizeof(road));
        cin>>N>>S;
        int i;
        road[S] = -1;
        for(i=0; i<N-1; ++i){
            int a,b;cin>>a>>b;
            city[a].push_back(b);
            city[b].push_back(a);
        }
        dfs(S);
        for(i=1; i<=N; ++i){
            cout<<road[i]<<" ";
        }
        cout<<endl;
    }
    return 0;
}
void dfs(int i){
    for(vector<int>::iterator iter=city[i].begin(); iter!=city[i].end(); iter++){
        if(road[(*iter)])continue;
        road[(*iter)] = i;
        dfs((*iter));
    }
}