poj 1823 Hotel 线段树，注意懒惰标记，不标记就会超时滴
#include<iostream>#include<cstdio>using namespace std;#define N 16005struct node{ int l,r,ml,mr,mm,len,sign;}a[N*4];void build(int i,int left,int right){ a[i].l=left; a[i].r=right; a[i].len=a[i].ml=a[i].mr=right-left+1; a[i].mm=0; a[i].sign=0;//表示这条边是否被用过 if(left==right) return ; int mid=(a[i].l+a[i].r)>>1; build(i*2,left,mid); build(i*2+1,mid+1,right);}void insert(int i,int left,int right,int sign){// cout<<a[i].l<<" "<<a[i].r<<"****"<<left<<" "<<right<<endl; if(a[i].l>=left&&a[i].r<=right){ a[i].sign=1; if(sign==1){ a[i].len=a[i].ml=a[i].mr=0; }else{ a[i].len=a[i].ml=a[i].mr=(a[i].r-a[i].l+1); } return ; } if(a[i].sign==1&&a[i].ml==0&&a[i].mr==0&&a[i].len==0){//懒惰标记 a[i*2+1].ml=a[i*2+1].mr=a[i*2+1].len=0; a[i*2].ml=a[i*2].mr=a[i*2].len=0; a[i*2+1].sign=a[i*2].sign=1; a[i].sign=0; } if(a[i].sign==1&&a[i].ml==(a[i].r-a[i].l+1)&&a[i].mr==(a[i].r-a[i].l+1)&&a[i].len==(a[i].r-a[i].l+1)){//懒惰标记 a[i*2+1].ml=a[i*2+1].mr=a[i*2+1].len=(a[i*2+1].r-a[i*2+1].l+1); a[i*2].ml=a[i*2].mr=a[i*2].len=(a[i*2].r-a[i*2].l+1); a[i*2+1].sign=a[i*2].sign=1; a[i].sign=0; } int mid=(a[i].l+a[i].r)>>1; if(right<=mid) insert(i*2,left,right,sign); else if(left>mid) insert(i*2+1,left,right,sign); else{ insert(i*2,left,mid,sign); insert(i*2+1,mid+1,right,sign); } a[i].len=max(a[i*2].mr+a[i*2+1].ml,max(a[i*2].len,a[i*2+1].len)); if(a[i*2+1].ml==(a[i*2+1].r-a[i*2+1].l+1)) a[i].mr=a[i*2].mr+a[i*2+1].ml; else a[i].mr=a[i*2+1].mr; if(a[i*2].mr==(a[i*2].r-a[i*2].l+1)) a[i].ml=a[i*2+1].ml+a[i*2].mr; else a[i].ml=a[i*2].ml; // cout<<"l="<<a[i].l<<" r="<<a[i].r<<" "<<a[i].ml<<" "<<a[i].len<<" "<<a[i].mr<<endl;}int main(){ int n,p,m,x,y; while(~scanf("%d%d",&n,&p)){ build(1,1,n); while(p--){ scanf("%d",&m); if(m==1){ scanf("%d%d",&x,&y);// cout<<"x+y-1="<<x+y-1<<endl; insert(1,x,x+y-1,1); }else if(m==2){ scanf("%d%d",&x,&y); insert(1,x,x+y-1,0); } else printf("%d\n",max(a[1].ml,max(a[1].len,a[1].mr))); } }}