- 并查集的有的神奇妙用是把一个问题我们倒过来考虑的时候,比如题目让我们分割一个数组或集合,我们考虑这个的逆过程,我们考虑用并查集考虑合并。
代码
#include <bits/stdc++.h>
using namespace std;
#define db double
#define ll long long
#define Pir pair<int, int>
#define fi first
#define se second
#define pb push_back
#define m_p make_pair
#define inf 0x3f3f3f3f
#define INF 0x3f3f3f3f3f3f3f3f
const int N = 1e5 + 10;
int fa[N], cnt[N];
int find(int x)
{
if (fa[x] == x) return x;
return fa[x] = find(fa[x]);
}
int main()
{
int n, m;
scanf("%d %d ", &n, &m);
for (int i = 1; i <= n; i ++) fa[i] = i, cnt[i] = 1;
string op; int x, y;
while (m --)
{
cin >> op;
if(op == "C")
{
cin >> x >> y;
int fx = find(x);
int fy = find(y);
if (fx != fy)
{
fa[fx] = fy;
cnt[fy] += cnt[fx];
}
}
else if (op == "Q1")
{
cin >> x >> y;
int fx = find(x);
int fy = find(y);
if (fx == fy)
printf("Yes\n");
else
printf("No\n");
}
else if (op == "Q2")
{
cin >> x;
int fx = find(x);
printf("%d\n", cnt[fx]);
}
}
return 0;
}