Luo Gu P4374

Is a board problem.

Note that the right side turn point to be removed right lca, directly id [x] is modified to add a.

Note that at this time, if x == y, directly returns.

code show as below:

#include<bits/stdc++.h>
using namespace std;
#define inf 2147483647
const int maxn=1e6;
int n,m;
inline int read(){
    int x=0,f=1;
    char c=getchar();
    while(c<'0'||c>'9'){
        if(c=='-')f=-1;
        c=getchar();
    }
    while(c>='0'&&c<='9'){
        x=(x<<1)+(x<<3)+c-'0';
        c=getchar();
    }
    return x*f;
}
int beg[maxn],nex[maxn],to[maxn],e;
inline void add(int x,int y){
    e++;nex[e]=beg[x];
    beg[x]=e;to[e]=y;
}
int xx[maxn],yy[maxn];
int son[maxn],size[maxn],dep[maxn],fa[maxn];
inline void dfs1(int x,int anc){
    dep [x] = dep [ANC] + 1 ;
    ago [x] = anc;
    size[x]=1;
    for(int i=beg[x];i;i=nex[i]){
        int t=to[i];
        if(t==anc)continue;
        dfs1(t,x);
        size[x]+=size[t];
        if(size[t]>size[son[x]])
            son[x]=t;
    }
}
int id[maxn],top[maxn],cnt;
inline void dfs2(int x,int topc){
    id[x]=++cnt;
    top[x]=topc;
    if(!son[x])return;
    dfs2(son[x],topc);
    for(int i=beg[x];i;i=nex[i]){
        int t=to[i];
        if(t==fa[x]||t==son[x])
            continue;
        dfs2(t,t);
    }
}
int tr[maxn],lazy[maxn];
inline void pushup(int h,int z){
    p [h] = min (p [h], z);
    lazy[h]=min(lazy[h],z);
}
inline void pushdown(int h){
    if(lazy[h]==inf)return;
    pushup(h<<1,lazy[h]);
    pushup(h<<1|1,lazy[h]);
    lazy[h]=inf;
}
inline void modify(int h,int l,int r,int x,int y,int z){
    if(l>y||r<x)return;
    if(l>=x&&r<=y){
        pushup(h,z);
        return;
    }
    pushdown(h);
    int mid=(l+r)>>1;
    modify(h<<1,l,mid,x,y,z);
    modify(h<<1|1,mid+1,r,x,y,z);
    //tr[h]=min(tr[h<<1],tr[h<<1|1]);
}
inline void mc(int x,int y,int z){
    while(top[x]!=top[y]){
        if(dep[top[x]]<dep[top[y]])swap(x,y);
        modify(1,1,n,id[top[x]],id[x],z);
        x=fa[top[x]];
    }
    if(x==y)return;
    if(dep[x]>dep[y])swap(x,y);
    modify(1,1,n,id[x]+1,id[y],z); 
}
/*
inline void build(int h,int l,int r){
    tr[h]=lazy[h]=inf;
    if(l==r)return;
    int mid=(l+r)>>1;
    build(h<<1,l,mid);
    build(h<<1|1,mid+1,r);
}
*/
inline int query(int h,int l,int r,int x){
    if(l==r)return tr[h];
    int mid=(l+r)>>1;
    pushdown(h);
    if(mid>=x)return query(h<<1,l,mid,x);
    else return query(h<<1|1,mid+1,r,x);
}
int main(){
    //freopen("p.in","r",stdin);
    n=read(),m=read();
    for(int i=0;i<=10*n;i++)
        tr[i]=lazy[i]=inf;
    for(int i=1;i<n;i++){
        xx[i]=read();
        yy[i]=read();
        add(xx[i],yy[i]);
        add(yy[i],xx[i]);
    }
    dfs1 ( 1 , 0 );
    dfs2(1,1);
    //build(1,1,n);
    int x,y,z;
    for(int i=1;i<=m;i++){
        x=read(),y=read(),z=read();
        mc(x,y,z);
    }
    int AC=0,WA=0;
    for(int i=1;i<n;i++){
        if(dep[xx[i]]<dep[yy[i]])swap(xx[i],yy[i]);
        int tmp=query(1,1,n,id[xx[i]]);
        tmp=(tmp==inf)?-1:tmp;
        printf("%d\n",tmp);
        /*x=read();
        if(x==tmp)AC++;
        else WA++,printf("%d %d\n",x,tmp);
        //printf("%d\n",tmp==inf?-1:tmp);
        */
    }
    //printf("%d %d\n",AC,WA);
    return 0;
}