楼房重建

线段树

bzoj2957

题解：

Code：

#include <iostream>#include <cstdio>#include <cstring>using namespace std;const int N = 100005;struct Node{    int l,r,mid;    int ans; double maxk;}t[N*4];void build(int num,int l,int r){    Node &now=t[num];    now.l=l; now.r=r; now.mid=(l+r)>>1;    now.ans=0; now.maxk=0.0;    if(l!=r){        build(num*2,l,now.mid);          build(num*2+1,now.mid+1,r);    }}int count(int num,double limit){    Node &now=t[num];    if(now.l==now.r) return now.maxk>limit;    Node &lch=t[num*2], &rch=t[num*2+1];    if(lch.maxk<=limit) return count(num*2+1,limit);    else return now.ans-lch.ans+count(num*2,limit);}void change(int num,int x,double k){    Node &now=t[num];    if(now.l==now.r){ now.ans=1; now.maxk=k; }    else{        if(x<=now.mid) change(num*2,x,k);        else change(num*2+1,x,k);        Node &lch=t[num*2], &rch=t[num*2+1];        now.maxk=max(lch.maxk,rch.maxk);        now.ans=lch.ans+count(num*2+1,lch.maxk);    }}void read(int &num){    num=0; char c;    while(!isdigit(c=getchar()));    num=c-'0';    while(isdigit(c=getchar()))num=num*10+c-'0';}int n,m;int main(){    freopen("building.in","r",stdin);    read(n); read(m);    build(1,1,n);    int x,y;    for(int i=1;i<=m;i++){        read(x); read(y);        change(1,x,double(y)/x);        printf("%d\n",t[1].ans);    }}