codevs1191 數軸染色

這個加上lazy也沒多大意義吧- -

#include<cstdio>
#include<iostream>
#include<cstring>
#include<cstdlib>
#include<algorithm>
#include<string>
#include<vector>
#include<map>
#include<set>
#include<queue>
#define R0(i,n) for(int i=0;i<n;++i)
#define R1(i,n) for(int i=1;i<=n;++i)
#define cl(x,c) memset(x,c,sizeof x)
#define INF 0x7fffffff
using namespace std;
typedef long long ll;
int read(){
    int x=0,f=1;char ch=getchar();
    while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
    while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
    return x*f;
}
int n,m;
struct node{
   int l,r,v,lazy;
}tr[800001];

void build(int k,int x,int y){
	tr[k].l=x;tr[k].r=y;
	if(x==y){tr[k].v=1;return;}
	int mid=(x+y)>>1;
	build(k<<1,x,mid);
	build(k<<1|1,mid+1,y);
	tr[k].v=tr[k<<1].v+tr[k<<1|1].v;
}
void change(int k,int x,int y){
	if(tr[k].v==0)return;
	int l=tr[k].l,r=tr[k].r;
	if(l==x&&r==y){tr[k].v=0;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 main(){
	int x,y;
	n=read(),m=read();
	build(1,1,n);
	R1(i,m){
		x=read(),y=read();
		change(1,x,y);
		printf("%d\n",tr[1].v);
	}
	return 0;
}