poj_2352树状数组

因为y已经排好序了，用x坐标建立一维树状数组

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
int n;
int a[32001];
int lev[15001];
int lowbit(int x)
{
    return x&(-x);
}
int sum(int x)
{
    int ret=0;
    while(x>0)
    {
        ret+=a[x];
        x-=lowbit(x);
    }
    return ret;
}
void add(int x,int d)
{
    while(x<=32001)
    {
        a[x]+=d;
        if(x!=0)
        x+=lowbit(x);
        else break;
    }
}
int main()
{

    while(scanf("%d",&n)!=EOF){
    memset(a,0,sizeof(a));
    memset(lev,0,sizeof(lev));
    int b,c;
    for(int i=0; i<n; i++)
    {
        scanf("%d%d",&b,&c);
        //add(b,1);
        b++;
        lev[sum(b)]++;
        add(b,1);
    }
    for(int i=0; i<n; i++)
        printf("%d\n",lev[i]);
    }
    return 0;
}