zoj 1789 The Suspects

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并查集

把所有的联通起来，然后查找0所在的圈子包含的数量就可以了

#include <iostream>#include <cstdio>using namespace std;#define N 30010int parent[N];int treeId[N];inline void init(int i){    treeId[i] = -1;}int find(int x){    if (treeId[x]>=0)    {        return treeId[x]=find(treeId[x]);    }    return x;}int main(){    int n,m;    while (scanf("%d %d",&n,&m)==2)    {        if (n==0&&m==0) break;        for (int i=0;i<n;i++)        {            init(i);        }        while(m--)        {            int nm;            scanf("%d",&nm);            int father;            int fatherParent =0;            if(nm>0)            {                scanf("%d",&father);                nm--;                fatherParent= find(father);            }            while(nm--)            {                int tmp;                scanf("%d",&tmp);                int tmpParent = find(tmp);                if(tmpParent!=fatherParent)                {                    treeId[fatherParent] += treeId[tmpParent];                    treeId[tmpParent] = fatherParent;                }            }        }        printf("%d\n",-treeId[find(0)]);    }    return 0;}