Luogu 2147 洞穴勘测

Solution

$LCT$ 打上 $cut$ ， $link$ 和 $finroot$ 即可

Code

#include<cstdio>
#include<cstring>
#include<algorithm>
#define rd read()
using namespace std;

const int N = 1e4 + 5;

int n, m;

int read() {
    int X = 0, p = 1; char c = getchar();
    for (; c > '9' || c < '0'; c = getchar())
        if (c == '-') p = -1;
    for (; c >= '0' && c <= '9'; c = getchar())
        X = X * 10 + c - '0';
    return X * p;
}

namespace LCT {
    int f[N], ch[N][2], tun[N];
#define lc(x) ch[x][0]
#define rc(x) ch[x][1]
    
    int isroot(int x) {
        return rc(f[x]) != x && lc(f[x]) != x;
    }

    int get(int x) {
        return rc(f[x]) == x;
    }

    void rev(int x) {
        swap(lc(x), rc(x));
        tun[x] ^= 1;
    }

    void pushdown(int x) {
        if (tun[x]) {
            if (lc(x)) rev(lc(x));
            if (rc(x)) rev(rc(x));
            tun[x] = 0;
        }
    }

    void pd(int x) {
        if (!isroot(x))
            pd(f[x]);
        pushdown(x);
    }
    
    void rotate(int x) {
        int old = f[x], oldf = f[old], son = ch[x][get(x) ^ 1];
        if (!isroot(old)) ch[oldf][get(old)] = x;
        ch[x][get(x) ^ 1] = old;
        ch[old][get(x)] = son;
        f[old] = x; f[x] = oldf; f[son] = old;
    }

    void splay(int x) {
        pd(x);
        for (; !isroot(x); rotate(x))
            if (!isroot(f[x]))
                rotate(get(f[x]) == get(x) ? f[x] : x);
    }

    void access(int x) {
        for (int y = 0; x; y = x, x = f[x])
            splay(x), ch[x][1] = y;
    }

    void mroot(int x) {
        access(x); splay(x); rev(x);
    }

    int findr(int x) {
        access(x); splay(x);
        while(lc(x)) pushdown(x), x = lc(x);
        return x;
    }

    void split(int x, int y) {
        mroot(x); access(y); splay(y);
    }
    
    void cut(int x, int y) {
        split(x, y);
        f[x] = ch[y][0] = 0;
    }

    void link(int x, int y) {
        mroot(x);
        f[x] = y;
    }
}using namespace LCT;

int main()
{
    n = rd; m = rd;
    for (; m; m--) {
        char op[10];
        scanf("%s", op);
        if (op[0] == 'Q') {
            int u = rd, v = rd;
            mroot(u); 
            if (findr(v) != u)
                puts("No");
            else puts("Yes");
        }
        if (op[0] == 'C') {
            int u = rd,  v = rd;
            link(u, v);
        }
        if (op[0] == 'D') {
            int u = rd, v = rd;
            cut(u, v);
        }
    }
}