树链剖分7WA其他AC

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
#include <queue>
#include <vector>
#include <cmath>
#include <string>
#include <cstdlib>
using namespace std;
const int maxn = 1e5+1;
const int INF = 2e9;
inline int read(){
    int x=0,f=1;char ch=getchar();
    while (ch<'0'||ch>'9'){if (ch=='-') f=-1;ch=getchar();}
    while (ch>='0'&&ch<='9'){x=x*10+ch-48;ch=getchar();}
    return x*f;
}
struct side{
    int pos,v,wt;
};
int n;
vector <side> tree[maxn];
int tmax[maxn*4],fa[maxn][20],size[maxn],idx[maxn],pos[maxn],bl[maxn],dep[maxn],len1[maxn],wt[maxn];
int *root[maxn],*cnt = tmax;
void dfs(int u,int Fa){
    fa[u][0] = Fa;
    dep[u] = dep[Fa]+1;
    size[u] = 1;
    for(int i = 1;i < 15;i++){
        fa[u][i] = fa[fa[u][i-1]][i-1];
    }
    for(int i = 0;i < tree[u].size();i++){
        if(tree[u][i].v!=Fa){
            int v = tree[u][i].v;
            idx[tree[u][i].pos] = v;
            wt[v] = tree[u][i].wt;
            dfs(v,u);
            size[u]+=size[v];
        }
    }
}
inline int *newTree(int len){
    int *ret = cnt;
    cnt+=4*len;
    return ret;
}
void insert(int *tmax,int i,int l,int r,int pos,int wt){
    if(l==r){
        tmax[i] = wt;
        return;
    }
    int mid = (l+r)>>1;
    if(pos<=mid) insert(tmax,i<<1,l,mid,pos,wt);
    else insert(tmax,(i<<1)+1,mid+1,r,pos,wt);
    tmax[i] = max(tmax[i<<1],tmax[(i<<1)+1]);
}
void dfs2(int u,int len,int Fa){
    int heavy = 0;
    for(int i = 0;i < tree[u].size();i++){
        int v = tree[u][i].v;
        if(v!=Fa&&size[v]>size[heavy]){
            heavy = v;
        }
    }
    if(!heavy){
        int tp = u;
        for(int i = 1;i < len;i++){
            tp = fa[tp][0];
        }
        root[tp] = newTree(len);
        len1[tp] = len;
        for(int i = len;i;i--){
            bl[u] = tp;
            pos[u] = i;
            insert(root[tp],1,1,len,i,wt[u]);
            u = fa[u][0];
        }
        return;
    }
    dfs2(heavy,len+1,u);
    for(int i = 0;i < tree[u].size();i++){
        int v = tree[u][i].v;
        if(v!=Fa&&v!=heavy)dfs2(v,1,u);
    }
}
void init(){
    n=read();
    for(int i = 1;i < n;i++){
        int r1=read(),r2=read(),r3=read();
        side s1;
        s1.pos=i;s1.v=r2;s1.wt=r3;
        tree[r1].push_back(s1);
        s1.v=r1;
        tree[r2].push_back(s1);
    }
    dfs(1,0);
    dfs2(1,1,0);
}
int LCA(int a,int b){
    if(dep[a]<dep[b])swap(a,b);
    for(int i = 15;i >= 0;i--){
        if(dep[a]-(1<<i)>=dep[b]){
            a = fa[a][i];
        }
    }
    if(a==b) return a;
    for(int i = 15;i >= 0;i--){
        if(fa[a][i]!=fa[b][i]){
            a = fa[a][i],b = fa[b][i];
        }
    }
    return fa[a][0];
}
int find(int *tmax,int i,int l,int r,int ll,int rr){
    if(l >= ll&&r <= rr){
        return tmax[i];
    }
    if(l > rr||r < ll){
        return -INF;
    }
    int mid = (l+r)>>1;
    return max(find(tmax,i<<1,l,mid,ll,rr),find(tmax,(i<<1)+1,mid+1,r,ll,rr));
}
int query(int lca,int a){
    int ret = 0;
    while(lca!=a){
        if(bl[lca] == bl[a]){ret = max(find(root[bl[a]],1,1,len1[bl[a]],pos[lca]+1,pos[a]),ret);break;}
        else ret = max(find(root[bl[a]],1,1,len1[bl[a]],1,pos[a]),ret),a = fa[bl[a]][0];
    }
    return ret;
}
void solve(){
    char c[10];int a,b,num=0;
    while(scanf("%s",c),c[0]!='D'){
        a=read(),b = read();
        if(c[0] =='Q'){
            if(++num == 49){
                int t = 0;
            }
            int lca = LCA(a,b);
            printf("%d\n",max(query(lca,a),query(lca,b)));
        }else{
            wt[idx[a]] = b;
            insert(root[bl[idx[a]]],1,1,len1[bl[idx[a]]],pos[idx[a]],b);
        }
    }
}
int main(){
//  freopen("4114.in","r",stdin);
//  freopen("4114.out","w",stdout);
    init();
    solve();
    return 0;
}