HDU 5178 Pairs (linear probing problem)

problem Description

John had n points on the X axis, and their coordinates is (X[i],0), (i=0,1,2,..., n−1 ). He wants to know what many pairs<a,b> that |x[b]−x[a]|≤k. (A<B)

Input

5 case begins with integers n,k (1≤n≤100000,1≤k≤109 ). Next n lines contain an integer x[i] (−109≤x[i]≤109

Output

case, output a integer means how many pairs<a,b> that |x[b]−x[a]|≤k.

Sample Input

2
5 5
-0101102

-0101102

Sample Output

3
10

Source Bestcoder Round #31 Test instructions: Given an array, ask how many pairs of <a,b> make| x[ B]− x[ A]| ≤k. (a< b) thinking: 1, the most important thing is to solve the problem of overtime, otherwise, according to the violence must be timed out.         2, resolving timeouts, here's a way.             First sort this array from small to large, then I start from 0, TMP starts from 0, if the value is less than or equal to K, tmp++ until >k stop ,             ans plus this value. Next time, i+1, before the I and K can, then and i < span class= "Mo" > +1 more can, all k continue to run backwards, so the complexity is greatly reduced. specific look at the code

1#include <iostream>2#include <cstdio>3#include <cstring>4#include <algorithm>5#include <stdlib.h>6#include <cmath>7 using namespacestd;8 #defineN 1000069 #definell Long LongTen intn,k; One intA[n]; A intMain () - { -     intT; thescanf"%d",&t); -      while(t--) -     { -scanf"%d%d",&n,&k); +          for(intI=0; i<n;i++) scanf ("%d",&a[i]); -Sort (a,a+n); +ll ans=0; A         inttmp=0; at          for(intI=0; i<n;i++) -         { -              while(ABS (a[i]-a[tmp]) <=k && tmp<n) tmp++; -ans=ans+tmp-i-1; -         } -printf"%i64d\n", ans); in     } -     return 0; to}

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HDU 5178 Pairs (linear probing problem)