【wikioi1191】 数轴染色

#include<iostream>#include<cstdio>using namespace std;struct data{int l,r,sum;bool tag;}tr[8500001];int n,m;void build(int k,int s,int t){tr[k].l=s;tr[k].r=t;if(s==t){tr[k].sum=1;return;}int mid=(s+t)>>1;build(k<<1,s,mid);build(k<<1|1,mid+1,t);tr[k].sum=tr[k<<1].sum+tr[k<<1|1].sum;}void update(int k,int s,int t){if(tr[k].tag){tr[k].sum=0;tr[k<<1].tag=tr[k<<1|1].tag=1;return;}int l=tr[k].l,r=tr[k].r;if(s==l&&t==r){tr[k].tag=1;tr[k].sum=0;return;}int mid=(l+r)>>1;if(t<=mid)update(k<<1,s,t);else if(s>mid)update(k<<1|1,s,t);else{update(k<<1,s,mid);update(k<<1|1,mid+1,t);}tr[k].sum=tr[k<<1].sum+tr[k<<1|1].sum;}int main(){scanf("%d %d",&n,&m);build(1,1,n);for(int i=1;i<=m;i++){int l,r;scanf("%d %d",&l,&r);update(1,l,r);printf("%d\n",tr[1].sum);}return 0;}