BZOJ4353 Play with tree[树剖]

复习几乎考不到的树剖。维护min以及min个数，打set和add标记即可，注意set优先级优于add。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#include<cmath>
#define dbg(x) cerr << #x << " = " << x <<endl
using namespace std;
typedef long long ll;
typedef double db;
typedef pair<int,int> pii;
template<typename T>inline T _min(T A,T B){return A<B?A:B;}
template<typename T>inline T _max(T A,T B){return A>B?A:B;}
template<typename T>inline char MIN(T&A,T B){return A>B?(A=B,1):0;}
template<typename T>inline char MAX(T&A,T B){return A<B?(A=B,1):0;}
template<typename T>inline void _swap(T&A,T&B){A^=B^=A^=B;}
template<typename T>inline T read(T&x){
    x=0;int f=0;char c;while(!isdigit(c=getchar()))if(c=='-')f=1;
    while(isdigit(c))x=x*10+(c&15),c=getchar();return f?x=-x:x;
}
const int N=1e5+7,INF=0x7f7f7f7f;
struct thxorz{int to,nxt;}G[N<<1];
int Head[N],tot;
int n,q;
inline void Addedge(int x,int y){
    G[++tot].to=y,G[tot].nxt=Head[x],Head[x]=tot;
    G[++tot].to=x,G[tot].nxt=Head[y],Head[y]=tot;
}
#define y G[j].to
int fa[N],son[N],topfa[N],st[N],dep[N],cnt,sonc[N];
void dfs1(int x,int f){
    int tmp=-1;sonc[x]=1;fa[x]=f,dep[x]=dep[f]+1;
    for(register int j=Head[x];j;j=G[j].nxt)if(y^f)dfs1(y,x),sonc[x]+=sonc[y],MAX(tmp,sonc[y])&&(son[x]=y);
}
void dfs2(int x,int topf){
    topfa[x]=topf,st[x]=cnt++;if(!son[x])return;dfs2(son[x],topf);//order the point in dfs2,not in dfs1.
    for(register int j=Head[x];j;j=G[j].nxt)if((y^fa[x])&&(y^son[x]))dfs2(y,y);
}
#undef y
#define lc i<<1
#define rc i<<1|1
#define all 1,1,n-1
int minv[N<<2],mint[N<<2],stag[N<<2],atag[N<<2];
inline void Pushup(int i){
    if(minv[lc]<minv[rc])mint[i]=mint[lc];
    else mint[i]=minv[lc]>minv[rc]?mint[rc]:mint[lc]+mint[rc];
    minv[i]=_min(minv[lc],minv[rc]);
}
inline void Pushdown(int i,int L,int R){
    if(~stag[i]){
        minv[lc]=minv[rc]=stag[i]+atag[i];
        atag[lc]=atag[rc]=atag[i],stag[lc]=stag[rc]=stag[i];
        mint[lc]=(L+R>>1)-L+1,mint[rc]=R-(L+R>>1);
        stag[i]=-1,atag[i]=0;
    }
    else{
        minv[lc]+=atag[i],minv[rc]+=atag[i];
        atag[lc]+=atag[i],atag[rc]+=atag[i];
        atag[i]=0;
    }
}
void Build(int i,int L,int R){
    if(L==R){mint[i]=1,stag[i]=-1;return;}
    int mid=L+R>>1;Build(lc,L,mid),Build(rc,mid+1,R),Pushup(i),stag[i]=-1;
}
void Update_set(int i,int L,int R,int ql,int qr,int c){
    if(ql<=L&&qr>=R){minv[i]=c,mint[i]=R-L+1,stag[i]=c,atag[i]=0;return;}
    int mid=L+R>>1;Pushdown(i,L,R);
    if(ql<=mid)Update_set(lc,L,mid,ql,qr,c);
    if(qr>mid)Update_set(rc,mid+1,R,ql,qr,c);
    Pushup(i);
}
void Update_add(int i,int L,int R,int ql,int qr,int c){
    if(ql<=L&&qr>=R){minv[i]+=c,atag[i]+=c;return;}
    int mid=L+R>>1;Pushdown(i,L,R);
    if(ql<=mid)Update_add(lc,L,mid,ql,qr,c);
    if(qr>mid)Update_add(rc,mid+1,R,ql,qr,c);
    Pushup(i);
}
int Query_min(int i,int L,int R,int ql,int qr){//dbg(i),dbg(ql),dbg(qr),dbg(minv[i]);
    if(ql<=L&&qr>=R)return minv[i];
    int mid=L+R>>1,ret=INF;Pushdown(i,L,R);
    if(ql<=mid)MIN(ret,Query_min(lc,L,mid,ql,qr));
    if(qr>mid)MIN(ret,Query_min(rc,mid+1,R,ql,qr));
    return ret;
}
inline void Tree_set(int x,int y,int c){
    while(topfa[x]^topfa[y]){
        if(dep[topfa[x]]<dep[topfa[y]])swap(x,y);//dbg(x);dbg(y);
        Update_set(all,st[topfa[x]],st[x],c);x=fa[topfa[x]];
    }
    if(dep[x]>dep[y])swap(x,y);
    if(x^y)Update_set(all,st[x]+1,st[y],c);
}
inline int Tree_min(int x,int y){
    int ret=INF;
    while(topfa[x]^topfa[y]){
        if(dep[topfa[x]]<dep[topfa[y]])swap(x,y);//dbg(x),dbg(st[topfa[x]]),dbg(st[x]);
        MIN(ret,Query_min(all,st[topfa[x]],st[x]));x=fa[topfa[x]];
    }
    if(dep[x]>dep[y])swap(x,y);
    if(x^y)MIN(ret,Query_min(all,st[x]+1,st[y]));
    return ret;
}
inline void Tree_add(int x,int y,int c){
    int minx=Tree_min(x,y);//dbg(minx);
    if(minx+c<0)c=-minx;
    while(topfa[x]^topfa[y]){
        if(dep[topfa[x]]<dep[topfa[y]])swap(x,y);
        Update_add(all,st[topfa[x]],st[x],c);x=fa[topfa[x]];
    }
    if(dep[x]>dep[y])swap(x,y);
    if(x^y)Update_add(all,st[x]+1,st[y],c);
}
int main(){//freopen("3.in","r",stdin);freopen("test.ans","w",stdout);
    read(n);read(q);
    for(register int i=1,x,y;i<n;++i)read(x),read(y),Addedge(x,y);
    dfs1(1,0);dfs2(1,1);Build(all);//for(register int i=1;i<=n;++i)cout<<i<<" ",dbg(st[i]);
    for(register int i=1,opt,x,y,c;i<=q;++i){
        read(opt),read(x),read(y),read(c);
        if(opt==1)Tree_set(x,y,c);
        else Tree_add(x,y,c);
        printf("%d
",!minv[1]?mint[1]:0);
    }
    return 0;
}