Poj2763Housewife Wind树链剖分

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#include<iostream>

#include<cstdio>

#include<cstring>

#include<map>

#include<vector>

#include<stdlib.h>

using namespace std;

typedef long long LL;

const int maxn = 222222;



struct Node

{

    int to;int next;

}e[maxn*2];

#define lson l,mid,rt<<1

#define rson mid+1,r,rt<<1|1



int head[maxn];

int son[maxn];

int top[maxn];

int father[maxn];

int deep[maxn];

int len;int z;

int size[maxn];

int pos[maxn];

int sum[maxn<<2];

void add(int from, int to)

{

    e[len].to = to;

    e[len].next = head[from];

    head[from] = len++;

}

int edge[maxn][10];



void init(int x)

{

    son[x] = 0; size[x] = 1;

    for (int i = head[x]; i != -1; i = e[i].next){

        int cc = e[i].to;

        if (cc == father[x]) continue;

        deep[cc] = deep[x] + 1; father[cc] = x;

        init(cc);

        size[x] += size[cc];

        if (size[son[x]] < size[cc]) son[x] = cc;

    }

}



void dfs(int x, int tp)

{

    pos[x] = ++z;top[x] = tp;

    if (son[x]) dfs(son[x], tp);

    for (int i = head[x]; i != -1; i = e[i].next){

        int cc = e[i].to;

        if (cc == father[x] || cc == son[x]) continue;

        dfs(cc, cc);

    }

}



void up(int rt)

{

    sum[rt] = sum[rt << 1] + sum[rt << 1 | 1];

}





void update(int key, int ans, int l, int r, int rt)

{

    if (l == r){

        sum[rt] = ans; return;

    }

    int mid = (l + r) >> 1;

    if (key <= mid) update(key, ans, lson);

    else update(key, ans, rson);

    up(rt);

}





int ask(int L, int R, int l, int r, int rt)

{

    if (L <= l&&r <= R) return sum[rt];

    int mid = (l + r) >> 1;

    int ans = 0;

    if (L <= mid) ans += ask(L, R, lson);

    if (R > mid) ans += ask(L, R, rson);

    return ans;

}



int gao(int x, int y)

{

    int ans = 0;

    int fx = top[x]; int fy = top[y];

    while (fx != fy){

        if (deep[fx] < deep[fy]){

            swap(fx, fy); swap(x, y);

        }

        ans += ask(pos[fx], pos[x], 1, z, 1);

        x = father[fx]; fx = top[x];

    }

    if (x == y) return ans;

    if (deep[x]>deep[y]) swap(x, y);

    ans += ask(pos[x] + 1, pos[y], 1, z, 1);

    return ans;

}



int main()

{

    int n,q,s;

    int a,b,c;

    while (cin >> n >> q >> s){

        memset(sum,0,sizeof(sum));

        len = 0;z =0;

        memset(head,-1,sizeof(head));

        deep[s]=1 ;

        for (int i = 1; i < n ; i++){

            scanf("%d%d%d", &edge[i][0], &edge[i][1], &edge[i][2]);

            add(edge[i][0], edge[i][1]); add(edge[i][1], edge[i][0]);

        }

        init(1); dfs(1, 1);

        for (int i = 1; i < n ; i++){

            int a = edge[i][0]; int b = edge[i][1]; int c = edge[i][2];

            if (deep[a]>deep[b]) swap(edge[i][0], edge[i][1]);

            update(pos[edge[i][1]], c, 1, z, 1);

        }

        while (q--){

            scanf("%d", &a);

            if (a == 0){

                scanf("%d", &b);

                int t = gao(b, s);

                cout << t << endl;

                s = b;

            }

            else {

                scanf("%d%d", &b, &c);

                edge[b][2] = c;

                update(pos[edge[b][1]], c, 1, z, 1);

            }

        }

    }

    return 0;

}