hdu 1541 Stars 树状数组模板题

#include<iostream>

#include<cstdio>

#include<cstring>

using namespace std;

const int  maxn=15010;

const int maxlen=32010;

int tree[4*maxn];

int lowbit(int n)

{

return (n&-n);

}

int getsum(int i)

{

int sum=0;

while(i>0)

{

sum+=tree[i];

i-=lowbit(i);

}

return sum;

}

void update(int i,int dx)

{

while(i<=maxlen)

{

tree[i]+=dx;

i+=lowbit(i);

}

}

int main()

{

int n;

int x,y;int i;

int ans[maxn];

while(scanf("%d",&n)!=EOF)

{

memset(ans,0,sizeof(ans));

memset(tree,0,sizeof(tree));

for(i=0;i<n;i++)

{

int x,y;

scanf("%d%d",&x,&y);

x++;

ans[getsum(x)]++;

update(x,1);

}

for(i=0;i<n;i++)

printf("%d\n",ans[i]);

}

return 0;

}