poj 2343 Airline company

poj 2343 Airline company

#include <stdio.h>#include <string.h>#include <iostream>#include <vector>#define maxn 52using namespace std;vector<int> a[maxn];int n,m,no;int f[maxn][maxn];int id[maxn*maxn];bool vis[maxn];void DFS(int u){    vis[u]=1;    int v;    for(int i=0;i<a[u].size();i++){        v=a[u][i];        if(!vis[v]){ id[f[u][v]]=++no; DFS(v);        }        else if(!id[f[u][v]]) id[f[u][v]]=++no;    }}int main(){    cin>>n>>m;    no=0;    memset(vis,0,sizeof(vis));    memset(id,0,sizeof(id));    int x,y;    for(int i=1;i<=m;i++){        scanf("%d%d",&x,&y);        a[x].push_back(y);        a[y].push_back(x);        f[x][y]=f[y][x]=i;    }    for(int i=1;i<=n;i++)        if(!vis[i]) DFS(i);    printf("YESn");    for(int i=1;i<m;i++)        printf("%d ",id[i]);    printf("%dn",id[m]);    return 0;}