Stars(树状数组)

#include <stdio.h>
const int N=32001;
int n,c
,level
;
int lowbit(int x)
{
return x&(-x);
}
int sum(int x)//求和
{
int s = 0;
while(x>0)
{
s += c[x];
x -= lowbit(x);
}
return s;
}
void update(int pos)//更新
{
while(pos <= N)
{
c[pos]++;
pos += lowbit(pos);
}
}
int main()
{
int x,y;
scanf("%d",&n);
for (int i = 1; i <= n; i++)
{
scanf("%d %d",&x,&y);
level[sum(x+1)]++;//树状数组的下标从一开始，故所有横坐标右移一位，相对位置不变
update(x+1);
}
for (int i = 0; i < n; i++)
printf("%d\n",level[i]);
return 0;
}