UVA10041 Vito’s family

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. 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) s1, s2, … , si, … , sr where they live (0 < si < 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 si and sj is dij = |si − sj |. Sample Input 2 2 2 4 3 2 4 6 Sample Output 2 4

題意

找一個房子，距離所有鄰居的門牌最近的房子。

解法

1. 先sort鄰居的門牌
2. 找出中位數（不是平均！）
3. 計算中位數與所有鄰居門牌的距離總和

程式碼

import java.util.Arrays;  
import java.util.Scanner;  
// NOTE: 於高中解題系統網站會出現使用太多空間錯誤，但在瘋狂程設是可以的  
public class Main {  
    public static void main(String[] args) {  
        Scanner sc = new Scanner(System.in);  
        int cases = sc.nextInt();  
  
        for(int i = 0 ; i < cases ;i++){  
            int[] relatives = new int[sc.nextInt()];  
            for(int x = 0; x < relatives.length; x++){  
               relatives[x] = sc.nextInt();  
            }  
            int sum = 0;  
            Arrays.sort(relatives);  
            int selected = relatives[relatives.length/2];  
            for(int y = 0 ; y < relatives.length ; y++){  
                sum += Math.abs(selected - relatives[y]);  
            }  
            System.out.println(sum);  
        }  
  
    }  
}