國中時的題目 用天秤找出一堆砝碼中唯一過重的那一個。

import java.util.Arrays;
import java.util.Random;

public class DrawingPanel {
 static int N = 8;
 public static void main(String[] args) {
  float balls[] = new float[N];
  Arrays.fill(balls, 1f);

  Random rand = new Random();
  balls[rand.nextInt(N) % balls.length] = 1.2f;
  
  int rs = compare(balls, 0, balls.length);
  
  for(int i = 0 ; i < balls.length ;i++){
   System.out.println(String.format("%c : %.1f", 'A'+i, balls[i]));
  }
  System.out.println("ans : " + (char)('A'+rs));
  
 }
 static int compare(float[] balls, int first, int last) {
  int size = last-first;
  if(size == 1){
   return first ;
  }
  int group = size / 3 ;
  if( size % 3 != 0)
   group = size / 3 + 1 ;
  
  float gp1 = sum(balls, first, first+group);
  float gp2 = sum(balls, first+group, first+2*group);
  if(gp1 > gp2){
   return compare(balls, first, first+group);
  }else if(gp1 < gp2){
   return compare(balls, first+group, first+2*group);
  }else{
   return compare(balls, first+2*group, last);
  }
  
 }
 static float sum(float arr[], int first, int last){
  float sum = 0f ;
  for(int i = first ; i < last ; i++)
   sum += arr[i];
  return sum ;
 }
}

這是在某個論壇回答人家問題的時候寫的!!
想到可以把他貼過來~~