洛谷P1501 [国家集训队]Tree II(LCT)

// luogu-judger-enable-o2
#include<iostream>
#include<cstdio>
#include<cstring>
#define int long long 
const int mod = 51061; 
using namespace std;
const int MAXN = 1e5+10;
inline int read() {
    char c = getchar(); int x = 0, f = 1;
    while(c < ‘0‘ || c > ‘9‘) {if(c == ‘-‘) f = -1; c = getchar();}
    while(c >= ‘0‘ && c <= ‘9‘) {x = x * 10 + c - ‘0‘; c = getchar();}
    return x * f;
}
int N, Q;
#define ls(x) T[x].ch[0]
#define rs(x) T[x].ch[1]
#define fa(x) T[x].f
struct node {
    int f, ch[2], r, mul, add, siz, sum, val;
}T[MAXN];
bool IsRoot(int x) {
    return T[fa(x)].ch[0] != x && T[fa(x)].ch[1] != x;
}
int ident(int x) {
    return T[fa(x)].ch[0] == x ? 0 : 1;
}
void connect(int x, int fa, int how) {
    T[x].f = fa;
    T[fa].ch[how] = x;
}
void update(int x) {
    T[x].sum = (T[ls(x)].sum + T[rs(x)].sum + T[x].val ) % mod;
    T[x].siz = T[ls(x)].siz + T[rs(x)].siz + 1 ;
}
void rotate(int x) {
    int Y = fa(x), R = fa(Y), Yson = ident(x), Rson = ident(Y);
    int B = T[x].ch[Yson ^ 1];
    T[x].f = R;
    if(!IsRoot(Y)) 
        connect(x, R, Rson);
    connect(B, Y, Yson);
    connect(Y, x, Yson ^ 1);
    update(Y);update(x);
}
void pushr(int x) {
    if(T[x].r) {
        swap(ls(x), rs(x));
        T[ls(x)].r ^= 1;
        T[rs(x)].r ^= 1;
        T[x].r = 0;
    }
}
void pushmul(int x) {
    T[ls(x)].val *= T[x].mul; T[ls(x)].val %= mod;
    T[rs(x)].val *= T[x].mul; T[rs(x)].val %= mod;
    T[ls(x)].sum *= T[x].mul; T[ls(x)].sum %= mod;
    T[rs(x)].sum *= T[x].mul; T[rs(x)].sum %= mod;
    T[ls(x)].add *= T[x].mul; T[ls(x)].add %= mod;
    T[rs(x)].add *= T[x].mul; T[rs(x)].add %= mod;
    T[ls(x)].mul *= T[x].mul; T[ls(x)].mul %= mod;
    T[rs(x)].mul *= T[x].mul; T[rs(x)].mul %= mod;
    T[x].mul = 1;
}
void pushadd(int x) {
    T[ls(x)].val += T[x].add; T[ls(x)].val %= mod;
    T[rs(x)].val += T[x].add; T[rs(x)].val %= mod;
    T[ls(x)].sum += T[ls(x)].siz * T[x].add; T[ls(x)].sum %= mod;
    T[rs(x)].sum += T[rs(x)].siz * T[x].add; T[rs(x)].sum %= mod;
    T[ls(x)].add += T[x].add; T[ls(x)].add %= mod;
    T[rs(x)].add += T[x].add; T[rs(x)].add %= mod;
    T[x].add = 0;
}
void pushdown(int x) {
    pushr(x);
    pushmul(x);
    pushadd(x);
}
int st[MAXN];
int fuck;
void splay(int x) {
    int y = x, top = 0;
    st[++top] = y;
    while(!IsRoot(y)) st[++top] = (y = fa(y));
    while(top) pushdown(st[top--]);
    for(int y = fa(x); !IsRoot(x); rotate(x), y = fa(x))
        if(!IsRoot(y))
            rotate( ident(x) == ident(y) ? y : x );
}
void access(int x) {
    for(int y = 0; x; x = fa(y = x))//tag
        splay(x), rs(x) = y, update(x);
}
void makeroot(int x) {
    access(x); 
    splay(x);
    T[x].r ^= 1;
}
void split(int x,int y) {
    makeroot(x);
    access(y);
    splay(y);
}
void link(int x, int y) {
    makeroot(x);
    T[x].f = y;
}
int findroot(int x) {
    access(x); 
    splay(x);
    while(ls(x)) x = ls(x);
    return x;
}
void cut(int x, int y) {
    split(x, y);
    //makeroot(x);
    if(findroot(y) == x && fa(x) == y && !rs(x))
        T[x].f = T[y].ch[0] = 0, update(y);
}
main() {
    freopen("a.in","r",stdin);
    scanf("%lld%lld", &N, &Q);
    for(int i = 1; i <= N; i++) 
        T[i].val = 1, T[i].sum = 1, T[i].mul = 1, T[i].siz = 1, T[i].add = 0;
    for(int i = 1; i <= N - 1; i++) {
        int x = read(), y = read();
        link(x, y);
    }
    int fuck = 0;
    while(Q--) {
        char c = 0; int u1, v1, u2, v2, val;
        while(c < ‘*‘) c = getchar(); 
        scanf("%lld%lld", &u1, &v1);
        if(c == ‘+‘) {
            scanf("%lld", &val);
            split(u1, v1);
            T[v1].val += val; T[v1].val %= mod;
            T[v1].add += val; T[v1].add %= mod;
            T[v1].sum += T[v1].siz * val; T[v1].sum %= mod;
        }    
        else if(c == ‘-‘) {
            scanf("%lld%lld", &u2, &v2);
            cut(u1, v1);
            link(u2, v2);
        }
        else if(c == ‘/‘) {
            split(u1, v1);
            printf("%d\n",T[v1].sum%mod);            
        }
        else {
            scanf("%lld",&val);
            split(u1, v1);
            T[v1].val *= val; T[v1].val %= mod;
            T[v1].sum *= val; T[v1].siz %= mod;
            T[v1].add *= val; T[v1].add %= mod;
            T[v1].mul *= val; T[v1].mul %= mod;
        }    
    }
    return 0;
}