UVA10041

Problem C: Vito's family

Background 

The world-known gangster Vito Deadstone is moving to New York. He has a very big family there, all of them living in Lamafia Avenue. Since he will visit all his relatives very often, he is trying to find a house close to them.

Problem 

Vito wants to minimize the total distance to all of them and has blackmailed you to write a program that solves his problem.

Input 

The input consists of several test cases. The first line contains the number of test cases.
For each test case you will be given the integer number of relatives r ( 0 < r < 500) and the street numbers (also integers) where they live ( 0 < s_i < 30000 ). Note that several relatives could live in the same street number.

Output 

For each test case your program must write the minimal sum of distances from the optimal Vito's house to each one of his relatives. The distance between two street numbers s_i and s_j is d_ij= |s_i-s_j|.

Sample Input 

2
2 2 4 
3 2 4 6

Sample Output 

2
4

大意:有個黑道老大想要住在離他所有親友最近的地方，給你一些親友的位址，問住在哪個街道上是最近的

解法:中位數

import java.util.*;

public class UVA10041 {

 public static void main(String[] args) {

  Scanner sc = new Scanner(System.in);

  int N = sc.nextInt();

  for (int i = 0; i < N; i++) {

   int r = sc.nextInt();

   int house[] = new int[r];

   for (int j = 0; j < r; j++) {

    house[j] = sc.nextInt();

   }
   Arrays.sort(house);

   int median = house[r / 2];

   int sum = 0;

   for (int k = 0; k < r; k++) {
    sum += Math.abs(house[k] - median);
   }

   System.out.println(sum);

  }

 }

}