Lightoj 1348 Aladdin and the Return Journey (树链剖分)（线段树单点修改区间求和）

#include <iostream>
#include <cstring>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <cmath>
#include <time.h>
#include <string>
#include <map>
#include <stack>
#include <vector>
#include <set>
#include <queue>
#define met(a,b) memset(a,b,sizeof a)
#define pb push_back
#define lson(x) ((x<<1))
#define rson(x) ((x<<1)+1)
using namespace std;
typedef long long ll;
const int N=2e5+50;
const int M=N*N+10;
int dep[N],siz[N],fa[N],id[N],son[N],val[N],top[N],c[N]; //top 最近的重链父节点
int num,n,m;
vector<int> v[N];
struct tree {
    int x,y;
    void read() {
        scanf("%d%d",&x,&y);
    }
};
tree e[N];
void dfs1(int u, int f, int d) {
    dep[u] = d;
    siz[u] = 1;
    son[u] = 0;
    fa[u] = f;
    for (int i = 0; i < v[u].size(); i++) {
        int ff = v[u][i];
        if (ff == f) continue;
        dfs1(ff, u, d + 1);
        siz[u] += siz[ff];
        if (siz[son[u]] < siz[ff])
            son[u] = ff;
    }
}
void dfs2(int u, int tp) {
    top[u] = tp;
    id[u] = ++num;
    if (son[u]) dfs2(son[u], tp);
    for (int i = 0; i < v[u].size(); i++) {
        int ff = v[u][i];
        if (ff == fa[u] || ff == son[u]) continue;
        dfs2(ff, ff);
    }
}

struct Tree {
    int l,r,val,sum;
};
Tree tree[4*N];
void pushup(int x) {
    tree[x].val = max(tree[lson(x)].val, tree[rson(x)].val);
    tree[x].sum=tree[lson(x)].sum+tree[rson(x)].sum;
}

void build(int l,int r,int v) {
    tree[v].l=l;
    tree[v].r=r;
    if(l==r) {
        tree[v].val = val[l];
        tree[v].sum=val[l];
        return ;
    }
    int mid=(l+r)>>1;
    build(l,mid,v*2);
    build(mid+1,r,v*2+1);
    pushup(v);
}
void update(int o,int v,int val) { //log(n)
    if(tree[o].l==tree[o].r) {
        tree[o].val =tree[o].sum= val;
        return ;
    }
    int mid = (tree[o].l+tree[o].r)/2;
    if(v<=mid)
        update(o*2,v,val);
    else
        update(o*2+1,v,val);
    pushup(o);
}
int querySum(int x,int l,int r) {
    if (tree[x].l >= l && tree[x].r <= r) {
        return tree[x].sum;
    }
    int mid = (tree[x].l + tree[x].r) / 2;
    int ans = 0;
    if (l <= mid) ans += querySum(lson(x),l,r);
    if (r > mid) ans += querySum(rson(x),l,r);
    return ans;
}
int Qsum(int u,int v) {
    int tp1 = top[u], tp2 = top[v];
    int ans = 0;
    while (tp1 != tp2) {
        if (dep[tp1] < dep[tp2]) {
            swap(tp1, tp2);
            swap(u, v);
        }
        ans +=querySum(1,id[tp1], id[u]);
        //printf("ans:   %d\n",ans);
        u = fa[tp1];
        tp1 = top[u];
    }
    //if (u == v) return ans;
    if (dep[u] > dep[v]) swap(u, v);
    ans +=querySum(1,id[u], id[v]);
    return ans;
}
void init(){
    for(int i=0;i<N;i++)v[i].clear();
    met(tree,0);met(son,0);met(val,0);
}
int main() {
    int t,T=0;
    scanf("%d",&t);
    while(t--) {
        init();
        ++T;
        scanf("%d",&n);
        for(int i=1; i<=n; i++)scanf("%d",&c[i]);
        for(int i=1; i<n; i++) {
            e[i].read();
            e[i].x++;e[i].y++;
            v[e[i].x].push_back(e[i].y);
            v[e[i].y].push_back(e[i].x);
        }

        num = 0;
        dfs1(1,0,1);
        dfs2(1,1);
        for (int i = 1; i <=n; i++) {
            val[id[i]] = c[i];
        }
        build(1,num,1);
        char s[200];
        scanf("%d",&m);
        printf("Case %d:\n",T);
        while(m--) {
            int o,x,y;
            scanf("%d",&o);
            scanf("%d%d",&x,&y);
            if (o)
                x++,update(1,id[x],y);
            else
                x++,y++,printf("%d\n",Qsum(x,y));
        }
    }
    return 0;
}