ZJU3686 线段树

#include <iostream>#include <algorithm>#include <cstdio>using namespace std;const int N=100009;struct Edge{    int v,next;}edge[N];struct Hash{    int a,b;}h[N];struct Tree{    int cover,val;}tree[N<<2];int cur,head[N];void dfs(int x){    if(x<=0) return;    cur++;    h[x].a=cur;    int e=head[x];    while(e>0)    {        dfs(edge[e].v);        e=edge[e].next;    }    h[x].b=cur;}void build(int l,int r,int id){    tree[id].cover=tree[id].val=0;    if(l<r)    {        int mid=(l+r)>>1;        build(l,mid,id<<1);        build(mid+1,r,id<<1|1);    }}void pushup(int id){    tree[id].val=tree[id<<1].val+tree[id<<1|1].val;}void pushdown(int l,int r,int id){    if(tree[id].cover)    {        tree[id<<1].cover ^= 1;        tree[id<<1|1].cover ^= 1;        int mid=(l+r)>>1;        tree[id<<1].val=mid-l+1-tree[id<<1].val;        tree[id<<1|1].val=r-mid-tree[id<<1|1].val;        tree[id].cover=0;    }}int answer(int L,int R,int l,int r,int id){    if(L<=l && r<=R) return tree[id].val;    pushdown(l,r,id);    int ans=0,mid=(l+r)>>1;    if(L<=mid) ans+=answer(L,R,l,mid,id<<1);    if(R>=mid+1) ans+=answer(L,R,mid+1,r,id<<1|1);    return ans;}void insert(int L,int R,int l,int r,int id){    if(L<=l && r<=R)    {        tree[id].cover^=1;        tree[id].val=r-l+1-tree[id].val;        return;    }    pushdown(l,r,id);    int mid=(l+r)>>1;    if(L<=mid) insert(L,R,l,mid,id<<1);    if(R>=mid+1) insert(L,R,mid+1,r,id<<1|1);    pushup(id);}int main(){    //freopen("in.txt","r",stdin);    int n,m,i,j,k,e;    ios::sync_with_stdio(false);    while(scanf("%d %d",&n,&m)==2)//cin>>n>>m)    {        for(i=1;i<=n;i++)        {            head[i]=0;            edge[i].next=0;        }        int en=1;        for(i=2;i<=n;i++)        {            scanf("%d",&k);//cin>>k;            edge[en].v=i;            edge[en].next=head[k];            head[k]=en++;        }        cur=0;        dfs(1);        build(1,n,1);        char o;        while(m--)        {            scanf("%*c %c %d",&o,&k);//cin>>o>>k;            if(o=='o') insert(h[k].a,h[k].b,1,n,1);            else printf("%d\n",answer(h[k].a,h[k].b,1,n,1));//cout<<answer(h[k].a,h[k].b,root,0)<<endl;            //for(i=1;i<=n;i++) cout<<h[i].a<<" "<<h[i].b<<endl;        }        puts("");    }    return 0;}