显示代码纯文本
#include<cstdio>
using namespace std;
typedef long long ll;
const int N =800005;
int n,m;
int flag[N];
inline int lson(int rt){return (rt<<1);}
inline int rson(int rt){return (rt<<1)|1;}
void update(int L,int R,int l,int r,int rt){
if(flag[rt])return;
if(L<=l && r<=R){
flag[rt]=r-l+1;
return;
}
int mid=(l+r)>>1;
if(mid>=L) update(L,R,l,mid,lson(rt));
if(mid<R) update(L,R,mid+1,r,rson(rt));
}
int query(int l,int r,int rt){
if(flag[rt])return flag[rt];
if(l==r)return 0;
int mid=(l+r)>>1,ans=0;
ans+=query(l,mid,lson(rt));
ans+=query(mid+1,r,rson(rt));
return ans;
}
int main(){
freopen("axis.in","r",stdin);
freopen("axis.out","w",stdout);
int i,l,r;
scanf("%d%d",&n,&m);
for(i=1;i<=m;i++){
scanf("%d%d",&l,&r);
update(l,r,1,n,1);
printf("%d\n",n-query(1,n,1));
}
return 0;
}