bzoj 2631

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

typedef long long ll;
const ll mod = 51061;
const ll maxn = 100010;

ll pl(ll a, ll b) {
    ll ret = a + b;
    if(ret >= mod) ret %= mod;
    return ret;
}

ll mul(ll a, ll b) {
    return a * b % mod;
}

struct node {
    ll ans, lm, lp, lr, size, data, p;
    node *son[2], *fa;
}e[maxn]; ll ne = 0;

void test(node* x) {
    if(!x) return;
    cout << x-> data <<" "<<x-> size <<" "<< x-> p << endl;
    for(ll i = 0; i < 2; ++ i) test(x-> son[i]);
}

void update(node* x) {
    x-> ans = x-> data, x-> size = 1;
    for(ll i = 0; i < 2; ++ i)
        if(x-> son[i]) 
            x-> ans = pl(x-> ans, x-> son[i]-> ans), x-> size = pl(x-> son[i]-> size, x-> size); 
}

void swap(node* &a, node* &b) {
    node* mid = a; a = b, b = mid;
}

void pushdown(node* x) {
    if(!x || (!x-> lp && !x-> lr && x-> lm == 1)) return;
    if(x-> lr) {
        swap(x-> son[0], x-> son[1]);
        for(ll i = 0; i < 2; ++ i) if(x-> son[i]) x-> son[i]-> lr ^= 1;
        x-> lr = 0;
    }
    for(ll i = 0; i < 2; ++ i) {
        if(x-> son[i]) { 
            x-> son[i]-> ans = pl(mul(x-> son[i]-> ans, x-> lm), mul(x-> son[i]-> size, x-> lp));
            x-> son[i]-> data = pl(mul(x-> son[i]->data, x-> lm), x-> lp);
            x-> son[i]-> lp = pl(mul(x-> son[i]-> lp, x-> lm), x-> lp);
            x-> son[i]-> lm = mul(x-> son[i]-> lm, x-> lm);
        }
    }
    x-> lm = 1, x-> lp = 0;  
}

void rotate(node* x, ll f) {
    node* y = x-> fa;
    if(y-> fa) {
        if(y-> fa-> son[0] == y) y-> fa-> son[0] = x;
        else y-> fa-> son[1] = x;
    }
    x-> fa = y-> fa; x-> size = y-> size; y-> fa = x; x-> p = y-> p;
    x-> ans = y-> ans; 
    y-> son[f] = x-> son[!f]; 
    if(x-> son[!f]) x-> son[!f]-> fa = y;
    x-> son[!f] = y;
    update(y);
}

void splay(node* x, node* f) {
    pushdown(x);
    while(x-> fa != f) {
        if(x-> fa-> fa == f) {
            pushdown(x-> fa-> fa), pushdown(x-> fa), pushdown(x);
            ll a = x-> fa-> son[0] == x ? 0 : 1;
            rotate(x, a);
        }
        else {
            node *y = x-> fa, *z = y-> fa;
            pushdown(z), pushdown(y), pushdown(x); 
            ll a = z-> son[0] == y ? 0 : 1;
            ll b = y-> son[0] == x ? 0 : 1;
            if(a == b) rotate(y, a), rotate(x, b);
            else rotate(x, b), rotate(x, a);
        }
    }
}

void access(ll cur) {
    node* x = e + cur; pushdown(x);
    node* y; splay(x, NULL);
    if(x-> son[1]) x-> son[1]-> p = cur, x-> son[1]-> fa = NULL, x-> son[1] = NULL;
    update(x);
    ll pp;
    while((pp = x-> p)) {
        y = e + pp; 
        splay(y, NULL); 
        if(y-> son[1]) y-> son[1]-> p = pp, y-> son[1]-> fa = NULL, y-> son[1] = NULL;
        y-> son[1] = x; 
        x-> fa = y;
        update(y);
        splay(x, NULL);
    }
}

void reserve(ll x) {
    access(x); 
    //test(x + e); cout << endl;
    (e + x)-> lr ^= 1;
}

ll n, m;

void link(ll a, ll b) {
    access(a);
    reserve(b);
    (e + b)-> p = a;
    update(e + a), update(e + b);
}

void cut(ll a, ll b) {
    reserve(a), access(b);
    //test(b + e); cout << endl;
    (e + a)-> p = 0, (e + a)-> fa = NULL, (e + b)-> son[0] = NULL;
    update(e + a), update(e + b);
}

ll ll_get() {
    ll x = 0; char c = (char)getchar();
    while(!isdigit(c) && c != ‘-‘) c = (char)getchar();
    bool f = 0; if(c == ‘-‘) f = 1, c = (char)getchar();
    while(isdigit(c)) {
        x = x * 10 + (ll)(c - ‘0‘);
        c = (char)getchar();
    }
    if(f) x = -x;
    return x;
}

struct edge {
    ll t; edge* next;
}se[maxn * 2], *head[maxn]; ll oe = 0;

void addedge(ll f, ll t) {
    se[oe].t = t, se[oe].next = head[f], head[f] = se + oe ++;
}

bool vis[maxn];

void build(ll x, ll pre) {
    vis[x] = 1;
    (e + x)-> p = pre; (e + x)-> data = (e + x)-> ans = 1; (e + x)-> size = 1; (e + x)-> lm = 1;
    for(edge* p = head[x]; p; p = p-> next) {
        if(!vis[p-> t]) build(p-> t, x);
    }
}

void read() {
    n = ll_get(), m = ll_get();
    for(ll i = 1; i < n; ++ i) {
        ll f = ll_get(), t = ll_get();
        addedge(f, t), addedge(t, f);
    }
    memset(vis, 0, sizeof(vis));
    build(1, 0);
}

void sov() {
    char s[10];
   // for(int i = 1; i <= n; ++ i) test(e + i), cout << endl;
        //cout << "****\n";
    while(m --) {
        scanf("%s", s + 1); 
        if(s[1] == ‘+‘) {
            ll a = ll_get(), b = ll_get(), c = ll_get();
            reserve(a); access(b); 
            node* x = (e + b);
            x-> lp = pl(c, x-> lp), x-> ans = pl(x-> ans, mul(c, x-> size)), x-> data = pl(x-> data, c);
        }
        if(s[1] == ‘*‘) {
            ll a = ll_get(), b = ll_get(), c = ll_get();
            reserve(a);
            access(b);
            node* x = (e + b);
            x-> lm = mul(x-> lm, c), x-> ans = mul(x-> ans, c), x-> data = mul(x-> data, c), x-> lp = mul(x-> lp, c);
        }
        if(s[1] == ‘-‘) {
            ll a, b, c, d; a = ll_get(), b = ll_get(), c = ll_get(), d = ll_get();
            cut(a, b);
            //for(int i = 1; i <= n; ++ i) cout << (e + i)-> p << endl<< endl;
            //for(int i = 1; i <= n; ++ i) test(e + i), cout << endl;
        //cout << "****\n";
            link(c, d);

            //for(int i = 1; i <= n; ++ i) test(e + i), cout << endl;
        
        }
        if(s[1] == ‘/‘) {
            ll a, b; a = ll_get(), b = ll_get(); 
            reserve(a), access(b); 
            printf("%lld\n", (e + b)-> ans);
        }
        //for(int i = 1; i <= n; ++ i) test(e + i), cout << endl;
        //cout << "****\n";
        //cout << (e + 1)-> son[0] << endl;
    }
}

int main() {
    //freopen("test.in", "r", stdin);
    //freopen("test.out", "w", stdout);
    read(); 
    sov();
}