poj 2481 Cows

Problem: 2481		User: shu_dayang
Memory: 2112K		Time: 1094MS
Language: C++		Result: Accepted

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#define MAXN  100005
using namespace std;

struct Cow
{
    int x;
    int y;
    int order;
}a[MAXN];

bool cmp(Cow a, Cow b)
{
    if(a.y != b.y) return a.y > b.y;
    return a.x < b.x;
}

int c[MAXN],num[MAXN];
int n;

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

void update(int x)
{
    while(x <= MAXN)
    {
        c[x]++;
        x += lowbit(x);
    }
}

int query(int x)
{
    int res = 0;
    while(x > 0)
    {
        res += c[x];
        x -= lowbit(x);
    }
    return res;
}

int main()
{
    int n;
    while( ~scanf("%d",&n) && n != 0)
    {
        for(int i = 1; i <= n; i++)
        {
            scanf("%d%d",&a[i].x,&a[i].y);
            a[i].x++;                                //防止出现0的情况而超时                                
            a[i].y++;
            a[i].order = i;
        }
        sort(a+1,a+1+n,cmp);
        memset(c,0,sizeof(c));
        memset(num,0,sizeof(num));
        update(a[1].x);
        num[1] = 0;
        for(int i = 2; i <= n; i++)
        {
            if(a[i].x == a[i-1].x && a[i].y == a[i-1].y)   //两头牛相同的情况
                num[a[i].order] = num[a[i-1].order];
            else
                num[a[i].order] = query(a[i].x);
            update(a[i].x);
        }
        for(int i = 1; i <= n; i++)
            printf("%d%c",num[i],(i==n)?'\n':' ');
    }
    return 0;
}