HDU 1213

最近家庭聚会也真不少，为啥做题这么应景...

水题，加上集合的利用，并查集

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <set>
using namespace std;

const int maxn= 1e3;

int pa[maxn];
int T, N, M;
set<int> grp;

int Find(int x)
{
    if (x== pa[x]){
        return x;
    }

    return pa[x]= Find(pa[x]);
}
void Merge(int x, int y)
{
    x= Find(x);
    y= Find(y);

    if (x== y){
        return;
    }

    pa[y]= x;
}
void Init(int n)
{
    grp.clear();
    for (int i= 1; i< n+1; ++i){
        pa[i]= i;
    }
}

int main()
{
    int x, y;
    scanf("%d", &T);

    for (int i= 0; i< T; ++i){
        scanf("%d %d", &N, &M);
        Init(N);
        for (int j= 0; j< M; ++j){
            scanf("%d %d", &x, &y);
            Merge(x, y);
        }
        for (int j= 1; j< N+1; ++j){
            grp.insert(Find(j));
        }
        printf("%d\n", int(grp.size()));
    }
    return 0;
}

标签：1213,HDU,return,grp,int,pa,include,Find
来源： https://www.cnblogs.com/Idi0t-N3/p/12236429.html