HDU 1213

题目大意：邀请n个人，要几张桌子，桌子特别大，多少人都坐的过。同一张桌子必须都是朋友，朋友的朋友也是朋友。

解题思路：与HDU1232几乎是一样的。

ac代码：

#include <iostream> #include <set>using namespace std;int t, n, m, pre[1005], t1, t2;set <int>se;int find(int x){int r=x, temp;while (r != pre[r])r = pre[r];while (r != x){temp = pre[x];pre[x] = r;x = temp;}return r;}void join(int x, int y){int fx=find(x), fy=find(y);if (fx != fy)pre[fx] = fy;}int main(){scanf("%d", &t);while (t--){scanf("%d%d", &n, &m);for (int i=1; i<=n; i++)pre[i] = i;for (int i=0; i<m; i++){scanf("%d%d", &t1, &t2);join(t1, t2);}for (int i=1; i<=n; i++)se.insert(find(i));printf("%d\n", se.size());se.clear();}return 0;}