2157: 旅游

题目链接：

dfs把边权送给点权

#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#include <vector>
#include <string>
using namespace std;
#define ll long long
#define re register
#define pb push_back
#define fi first
#define se second
const int N=1e6+10;
const int mod=998244353;
void read(int &a)
{
    a=0;int d=1;char ch;
    while(ch=getchar(),ch>'9'||ch<'0')
        if(ch=='-')
            d=-1;
    a=ch^48;
    while(ch=getchar(),ch>='0'&&ch<='9')
        a=(a<<3)+(a<<1)+(ch^48);
    a*=d;
}
struct node{int x,w,p;};
struct note
{
    int l,r,ma,mi,sum,lazy;
}tree[N<<2];
vector <node> v[N];
int siz[N],top[N],dep[N],son[N],id[N],rk[N],f[N],val[N],rt=1,cnt,head[N];
void dfs1(int x)
{
    siz[x]=1,dep[x]=dep[f[x]]+1;
    for(re int t=0;t<v[x].size();t++)
    {
        node i=v[x][t];
        if(i.x!=f[x])
        {
            val[i.x]=i.w;
            head[i.p]=i.x;
            f[i.x]=x,dfs1(i.x);
            siz[x]+=siz[i.x];
            if(siz[son[x]]<siz[i.x]) son[x]=i.x;
        }
    }
}
void dfs2(int x,int tp)
{
    top[x]=tp,id[x]=++cnt,rk[cnt]=x;
    if(son[x]) dfs2(son[x],tp);
    for(re int t=0;t<v[x].size();t++) {node i=v[x][t];if(i.x!=son[x]&&i.x!=f[x]) dfs2(i.x,i.x);}
}
void build(int l,int r,int now)
{
    tree[now].l=l,tree[now].r=r,tree[now].lazy=0;
    if(l==r) {tree[now].sum=val[rk[l]],tree[now].ma=val[rk[l]],tree[now].mi=val[rk[l]];return;}
    int m=l+r>>1;
    build(l,m,now<<1),build(m+1,r,now<<1|1);
    tree[now].sum=(tree[now<<1].sum+tree[now<<1|1].sum);
    tree[now].mi=min(tree[now<<1].mi,tree[now<<1|1].mi);
    tree[now].ma=max(tree[now<<1].ma,tree[now<<1|1].ma);
}
void work(int now,int k)
{
    tree[now].sum=-tree[now].sum;
    int x=tree[now].ma,y=tree[now].mi;
    tree[now].ma=-y,tree[now].mi=-x;
    tree[now].lazy^=k;
}
void pushdown(int now)
{
    work(now<<1,tree[now].lazy);
    work(now<<1|1,tree[now].lazy);
    tree[now].lazy=0;
}
void modify(int l,int r,int now,int w)
{
    if(l<=tree[now].l&&tree[now].r<=r) {work(now,w);return;}
    if(tree[now].lazy) pushdown(now);
    int m=tree[now].l+tree[now].r>>1;
    if(m>=l) modify(l,r,now<<1,w);
    if(m<r) modify(l,r,now<<1|1,w);
    tree[now].sum=(tree[now<<1].sum+tree[now<<1|1].sum);
    tree[now].ma=max(tree[now<<1].ma,tree[now<<1|1].ma);
    tree[now].mi=min(tree[now<<1].mi,tree[now<<1|1].mi);
}
void mo(int l,int now,int w)
{
    if(tree[now].l==l&&tree[now].r==l) {tree[now].sum=w,tree[now].ma=w,tree[now].mi=w;return;}
    if(tree[now].lazy) pushdown(now);
    int m=tree[now].l+tree[now].r>>1;
    if(m>=l) mo(l,now<<1,w);
    if(m<l) mo(l,now<<1|1,w);
    tree[now].sum=(tree[now<<1].sum+tree[now<<1|1].sum);
    tree[now].mi=min(tree[now<<1].mi,tree[now<<1|1].mi);
    tree[now].ma=max(tree[now<<1].ma,tree[now<<1|1].ma);
}
int query(int l,int r,int now)
{
    int ans=0;
    if(l<=tree[now].l&&tree[now].r<=r) {return tree[now].sum;}
    if(tree[now].lazy) pushdown(now);
    int m=tree[now].l+tree[now].r>>1;
    if(m>=l) ans+=query(l,r,now<<1);
    if(m<r) ans+=query(l,r,now<<1|1);
    return ans;
}
int queryy(int l,int r,int now)
{
    int ans=-0x3fffffff;
    if(l<=tree[now].l&&tree[now].r<=r) {return tree[now].ma;}
    if(tree[now].lazy) pushdown(now);
    int m=tree[now].l+tree[now].r>>1;
    if(m>=l) ans=max(ans,queryy(l,r,now<<1));
    if(m<r) ans=max(ans,queryy(l,r,now<<1|1));
    return ans;
}
int queryyy(int l,int r,int now)
{
    int ans=0x3fffffff;
    if(l<=tree[now].l&&tree[now].r<=r) {return tree[now].mi;}
    if(tree[now].lazy) pushdown(now);
    int m=tree[now].l+tree[now].r>>1;
    if(m>=l) ans=min(ans,queryyy(l,r,now<<1));
    if(m<r) ans=min(ans,queryyy(l,r,now<<1|1));
    return ans;
}
void update(int x,int y,int w)
{
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        modify(id[top[x]],id[x],1,w);
        x=f[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    modify(id[x]+1,id[y],1,w);
}
int query1(int x,int y)
{
    int ans=0;
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans+=query(id[top[x]],id[x],1);
        x=f[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    return ans+query(id[x]+1,id[y],1);
}
int query2(int x,int y)
{
    int ans=-0x3fffffff;
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans=max(ans,queryy(id[top[x]],id[x],1));
        x=f[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    return ans=max(ans,queryy(id[x]+1,id[y],1));
}
int query3(int x,int y)
{
    int ans=0x3fffffff;
    while(top[x]!=top[y])
    {
        if(dep[top[x]]<dep[top[y]]) swap(x,y);
        ans=min(ans,queryyy(id[top[x]],id[x],1));
        x=f[top[x]];
    }
    if(dep[x]>dep[y]) swap(x,y);
    return ans=min(ans,queryyy(id[x]+1,id[y],1));
}
int main()
{
    int n;read(n);
    for(re int i=1,x,y,z;i<n;i++)
    {
        read(x),read(y),read(z);
        x++,y++;
        v[x].pb(node{y,z,i});
        v[y].pb(node{x,z,i});
    }
    dfs1(rt),dfs2(rt,rt);
    build(1,n,1);
    int m;read(m);
    char op[10];
    for(re int i=1,l,r;i<=m;i++)
    {
        scanf("%s",op);
        read(l),read(r); l++,r++;
        if(op[0]=='C') l--,r--,mo(id[head[l]],1,r);
        else if(op[0]=='N') update(l,r,1);
        else if(op[0]=='S') printf("%d
",query1(l,r));
        else if(op[0]=='M'&&op[1]=='A') printf("%d
",query2(l,r));
        else if(op[0]=='M'&&op[1]=='I') printf("%d
",query3(l,r));
    }
    return 0;
}