【codevs 1690】题解

#include<cstdio>
#include<iostream>
using namespace std;
int n,m;
struct data{
int l,r,v;
bool lazy;
}tr[2000001];
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].lazy)return;
tr[k<<1].lazy=!tr[k<<1].lazy;
tr[k<<1|1].lazy=!tr[k<<1|1].lazy;
tr[k<<1].v=tr[k<<1].r-tr[k<<1].l+1-tr[k<<1].v;
tr[k<<1|1].v=tr[k<<1|1].r-tr[k<<1|1].l+1-tr[k<<1|1].v;
tr[k].lazy=0;
}
void change(int k,int x,int y)
{
pushdown(k);
int l=tr[k].l,r=tr[k].r;
if(l==x&&r==y)
{
tr[k].v=y-x+1-tr[k].v;
if(l!=r)tr[k].lazy=1;
return;
}
int mid=(l+r)>>1;
if(mid>=y)change(k<<1,x,y);
else if(mid<x)change(k<<1|1,x,y);
else {change(k<<1,x,mid);change(k<<1|1,mid+1,y);}
tr[k].v=tr[k<<1].v+tr[k<<1|1].v;
}
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].v;
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 flag,x,y;
scanf("%d%d%d",&flag,&x,&y);
if(flag)printf("%d\n",ask(1,x,y));
else change(1,x,y);
}
return 0;
}