Codeforces Round #442 (Div. 2) E. Danil and a Part-time Job【线段树+dfs序】

对原来的图进行一波dfs，序列化，用线段树维护。查询就是线段树上区间查询，修改时可以用延迟标记一下。

/* ***********************************************Author        :xiang578Email         :[e-mail] Time  :Mon Nov  6 14:30:42 2017File Name     :cf877e.cpp************************************************ */#include <stdio.h>#include <string.h>#include <iostream>#include <algorithm>#include <vector>#include <queue>#include <set>#include <map>#include <string>#include <math.h>#include <stdlib.h>#include <time.h>using namespace std;const int n=400000+10;int N,sum[4*n],lazy[4*n],in[n],out[n],a[n],mp[n],cnt;vector<int>g[n];void dfs(int x){    in[x]=++cnt;    mp[cnt]=x;    for(int i=0;i<g[x].size();i++)        dfs(g[x][i]);    out[x]=cnt;}void build(int rt,int l,int r){    lazy[rt]=0;    if(l==r) {sum[rt]=a[mp[l]];}    else {        int mid = (l+r)/2;        build(rt*2,l,mid);        build(rt*2+1,mid+1,r);        sum[rt]=sum[rt*2]+sum[rt*2+1];    }}void pushdown(int rt,int l,int r){    lazy[rt]=0;    int mid=(l+r)/2;    sum[rt*2]=mid-l+1-sum[rt*2];    sum[rt*2+1]=r-(mid+1)+1-sum[rt*2+1];    lazy[rt*2]^=1;    lazy[rt*2+1]^=1;}int query(int rt,int l,int r,int ql,int qr){    if(l>=ql&&r<=qr)    {        return sum[rt];    }    else    {        int mid = (l+r)/2;        if(lazy[rt]) pushdown(rt,l,r);        int ret=0;        if(mid>=ql) ret+=query(rt*2,l,mid,ql,qr);        if(mid+1<=qr) ret+=query(rt*2+1,mid+1,r,ql,qr);        return ret;    }}void change(int rt,int l,int r,int ql,int qr){    if(l>=ql&&qr>=r)    {        sum[rt]=r-l+1-sum[rt];        lazy[rt]^=1;    }    else{        int mid = (l+r)/2;        if(lazy[rt]) pushdown(rt,l,r);        if(mid>=ql) change(rt*2,l,mid,ql,qr);        if(mid+1<=qr) change(rt*2+1,mid+1,r,ql,qr);        sum[rt]=sum[rt*2]+sum[rt*2+1];    }}int main(){    //freopen("in.txt","r",stdin);    //freopen("out.txt","w",stdout);    cnt=0;    scanf("%d",&N);    for(int i=2;i<=N;i++)    {        int t;        scanf("%d",&t);        g[t].push_back(i);    }    dfs(1);    for(int i=1;i<=N;i++)    {        scanf("%d",a+i);    }    build(1,1,N);    int m;    scanf("%d",&m);    while(m--)    {        char s[10];        int c;        scanf("%s%d",s,&c);        if(s[0]=='g')        {            //printf("%d %d\n",in[c],out[c]);            printf("%d\n",query(1,1,N,in[c],out[c]));        }        else        {            //printf("%d %d\n",in[c],out[c]);            change(1,1,N,in[c],out[c]);        }    }    return 0;}