《1612: Cube Stacking 》

和hdu那题一样也是带权并查集。

考虑从最下面为根，那么根的ans = 0，路径压缩之后0就不会一直更新影响了。

然后需要注意的点，P不是点数，应该将N全初始化，就是这里一直TLE。

然后注意询问前先路径压缩一下，因为可能之前没有更新到。

#include<bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<int,int> pii;
const int N = 3e4+5;
const int M = 1e6+5;
const LL Mod = 1e9 + 7;
#define pi acos(-1)
#define INF 1e18
#define CT0 cin.tie(0),cout.tie(0)
#define IO ios::sync_with_stdio(false)
#define dbg(ax) cout << "now this num is " << ax << endl;
namespace FASTIO{
    inline LL read(){
        LL x = 0,f = 1;char c = getchar();
        while(c < '0' || c > '9'){if(c == '-')f = -1;c = getchar();}
        while(c >= '0' && c <= '9'){x = (x << 1) + (x << 3) + (c ^ 48);c = getchar();}
        return x * f;
    }
}
using namespace FASTIO;

int fa[N],ans[N],sz[N];
int Find(int x)
{
    if(x == fa[x]) return x;
    else
    {
        int ffa = fa[x];
        fa[x] = Find(fa[x]);
        ans[x] = ans[ffa] + ans[x];
        return fa[x];
    }
}
int main()
{
    int n;n = read();
    for(int i = 1;i < N;++i) fa[i] = i,ans[i] = 0,sz[i] = 1;
    for(int i = 1;i <= n;++i)
    {
        char c;scanf("%c",&c);
        if(c == 'M')
        {
            int x,y;x = read(),y = read();
            int xx = Find(x),yy = Find(y);
            if(xx != yy)
            {
                fa[xx] = yy;
                ans[xx] = sz[yy]; 
                sz[yy] += sz[xx];
            }
        }
        else 
        {
            int x;x = read();
            int ma = Find(x);
            printf("%d
",ans[x]);
        }
    }
    system("pause");
    return 0;
}