P3088 [USACO13NOV]挤奶牛Crowded Cows

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  • 题目提供者 FarmerJohn2
  • 评测方式 云端评测
  • 标签 单调队列 概率论,统计 队列 USACO 2013 高性能
  • 难度 普及+/提高
  • 时空限制 1000ms / 128MB

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    题目描述

    Farmer John's N cows (1 <= N <= 50,000) are grazing along a one-dimensional fence. Cow i is standing at location x(i) and has height h(i) (1 <= x(i),h(i) <= 1,000,000,000).

    A cow feels "crowded" if there is another cow at least twice her height within distance D on her left, and also another cow at least twice her height within distance D on her right (1 <= D <= 1,000,000,000). Since crowded cows produce less milk, Farmer John would like to count the number of such cows. Please help him.

    FJ有N(1 <= N <= 50,000)头奶牛沿着一维的栅栏吃草,第i头奶牛在目标点x(i) ,它的身高是 h(i) (1 <=x(i),h(i) <= 1,000,000,000)。

    当一头奶牛左边D距离内而且右边D距离内有身高至少是它的两倍的奶牛,t (1 <= D <= 1,000,000,000),它就会觉得拥挤。

    请计算觉得拥挤的奶牛的数量。

    输入输出格式

    输入格式:

    * Line 1: Two integers, N and D.

    * Lines 2..1+N: Line i+1 contains the integers x(i) and h(i). The locations of all N cows are distinct.

    输出格式:

    * Line 1: The number of crowded cows.

    输入输出样例

    输入样例#1: 复制
    6 4 
    10 3 
    6 2 
    5 3 
    9 7 
    3 6 
    11 2 
    
    输出样例#1: 复制
    2 
    

    说明

    There are 6 cows, with a distance threshold of 4 for feeling crowded. Cow #1 lives at position x=10 and has height h=3, and so on.

    The cows at positions x=5 and x=6 are both crowded.

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