poj 2352 Stars 树状数组

#include<stdio.h>
#include<string.h>

int a[32002];
int level[15002];

int lowbit(int x)
{
	return x&(-x);
}

void insert(int x)
{
	while(x<32002)
	{
		a[x]++;
		x += lowbit(x);
	}
}

int sum(int x)
{
	int s=0;
	while(x)
	{
		s += a[x];
		x -= lowbit(x);
	}
	return s;
}

int main()
{
	int n, i, x, y;
	scanf("%d",&n);
	memset(a,0,sizeof(level));
	memset(level,0,sizeof(level));
	for(i = 0; i < n; i++)
	{
		scanf("%d%d",&x,&y);
		x++;
		level[sum(x)]++;
		insert(x);
	}
	for(i= 0; i < n; i++)
		printf("%d\n",level[i]);
	return 0;
}