CF877E Danil and a Part-time Job

维护子树和。dfs序就搞定。树剖用不上。
记得，取反时标记取反而不是打上！

#include<bits/stdc++.h>
using namespace std;
const int maxn=2e5+5;
int sze[maxn],dfn[maxn],rev[maxn];
int xds[maxn<<2],tag[maxn<<2];
int a[maxn];
int n,m;
vector<int> e[maxn];
void dfs(int u,int f){
	dfn[u]=++dfn[0];
    rev[dfn[0]]=u;
	sze[u]=1;
	for(auto x:e[u]){
		if(x!=f){
			dfs(x,u);
			sze[u]+=sze[x];
		}
	}
}
void pushup(int k){
	xds[k]=xds[k<<1]+xds[k<<1|1];
}
void flip(int k,int l,int r){
	xds[k]=(r-l+1)-xds[k];
	tag[k]^=1;
}
void build(int k,int l,int r){
	tag[k]=0;
	if(l==r){
		xds[k]=a[rev[l]];
		return ;
	}
	int mid=l+r>>1;
	build(k<<1,l,mid);
	build(k<<1|1,mid+1,r);
	pushup(k);
}
void pushdown(int k,int l,int r){
	int mid=l+r>>1;
	if(tag[k]){
		flip(k<<1,l,mid);
		flip(k<<1|1,mid+1,r);
		tag[k]=0;
		pushup(k);
	}
} 
void modify(int k,int l,int r,int x,int y){
 //cout<<"modify"<<xds[k]<<" "<<l<<" "<<r<<" "<<x<<" "<<y<<" "<<tag[k]<<endl;
	if(x<=l&&r<=y)return flip(k,l,r);
	int mid=l+r>>1;
	pushdown(k,l,r);
	if(x<=mid)modify(k<<1,l,mid,x,y);
	if(mid<y)modify(k<<1|1,mid+1,r,x,y);
	pushup(k);
}
int query(int k,int l,int r,int x,int y){
   // cout<<xds[k]<<" "<<l<<" "<<r<<" "<<x<<" "<<y<<" "<<tag[k]<<endl;
    if(x<=l&&r<=y)return xds[k];
	int mid=l+r>>1;int res=0;
	pushdown(k,l,r);
	if(x<=mid)res+=query(k<<1,l,mid,x,y);
	if(mid<y)res+=query(k<<1|1,mid+1,r,x,y);
	return res;
}
int main(){
	cin>>n;
	for(int i=2;i<=n;i++){
		int x;
		cin>>x;
		e[x].push_back(i);
		e[i].push_back(x);
	}
	for(int i=1;i<=n;i++)cin>>a[i];
	cin>>m;
	dfs(1,0);
	build(1,1,n);
	for(int i=1;i<=m;i++){
		string f;int x;
		cin>>f>>x;
		if(f[0]=='g')cout<<query(1,1,n,dfn[x],dfn[x]+sze[x]-1)<<endl;
		else modify(1,1,n,dfn[x],dfn[x]+sze[x]-1);
	}
	return 0; 
}

标签：xds,int,dfs,sze,Job,Part,maxn,time,dfn
来源： https://www.cnblogs.com/kkksc0100/p/CF877E.html