ural 1080. Map Coloring（二分染色bfs）

#include <iostream>#include <cstdio>#include <cstring>#include <queue>using namespace std;int  map[105][105];int  pay[105];int n;queue<int>Q;void init(){        memset(pay,-1,sizeof(pay));    memset(map,0,sizeof(map));    while (!Q.empty())    {        Q.pop();    }}int BFS(int x){    int i,v;    Q.push(x);    pay[x]=0;    while (!Q.empty())    {        v=Q.front();        Q.pop();        for(i=1;i<=n;i++)        {            if(map[v][i])            {                if(pay[i]==-1)                {                                        pay[i]=1-pay[v];                    Q.push(i);                }                else if(pay[v]==pay[i]) return 0;            }        }    }    return 1; }int main(){    int k,i,x;    while (scanf("%d",&n)!=EOF)    {        init();        for (i=1;i<=n;i++)        {            while (scanf("%d",&x),x)            {                map[i][x]=1;                map[x][i]=1;            }        }        k=BFS(1);                if(k==0){printf("-1\n");continue;}        for (i=1;i<=n;i++)            printf("%d",pay[i]);        printf("\n");    }    return 0;}