【wikioi1690】 开关灯

#include<iostream>
#include<cstdio>
using namespace std;
struct data{
	int l,r,sum;
	bool tag;
}tr[2000001];
int n,m;
void build(int k,int s,int t)
{
     tr[k].l=s;tr[k].r=t;
     if(s==t)return;
     int mid=(s+t)>>1;
     build(k<<1,s,mid);
     build(k<<1|1,mid+1,t);
}
void pushdown(int k)
{   
     if(!tr[k].tag)return;
     tr[k<<1].tag=!tr[k<<1].tag;
     tr[k<<1|1].tag=!tr[k<<1|1].tag;
     tr[k<<1].sum=tr[k<<1].r-tr[k<<1].l+1-tr[k<<1].sum;
     tr[k<<1|1].sum=tr[k<<1|1].r-tr[k<<1|1].l+1-tr[k<<1|1].sum;
     tr[k].tag=0;
}
void update(int k,int x,int y)
{
	 pushdown(k);
     int l=tr[k].l,r=tr[k].r;
     if(l==x&&r==y)
     {
          tr[k].sum=y-x+1-tr[k].sum;
          if(l!=r)tr[k].tag=1;
          return;
          }
     int mid=(l+r)>>1;
     if(mid>=y)update(k<<1,x,y);
     else if(mid<x)update(k<<1|1,x,y);
     else {update(k<<1,x,mid);update(k<<1|1,mid+1,y);}
     tr[k].sum=tr[k<<1].sum+tr[k<<1|1].sum;
}
int ask(int k,int x,int y)	
{
	pushdown(k);
    int l=tr[k].l,r=tr[k].r;
    if(l==x&&y==r)return tr[k].sum;
    int mid=(l+r)>>1;
    if(mid>=y)return ask(k<<1,x,y);
    else if(mid<x)return ask(k<<1|1,x,y);
    else return (ask(k<<1,x,mid)+ask(k<<1|1,mid+1,y));
}
int main()
{
	scanf("%d %d",&n,&m);
	build(1,1,n);
	for(int i=1;i<=m;i++){
		int temp,x,y;
		scanf("%d %d %d",&temp,&x,&y);
		if(temp==0)update(1,x,y);
		else printf("%d\n",ask(1,x,y));
	}
	return 0;
}