无序数组a，求a[i]-a[j]的最大值，且i<j

一道面试题：对于无序数组a，求a[i]-a[j]的最大值，其中i<j

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 package test;

 import java.util.Arrays;

 public class FindMax {
     public static void main(String[] args) {
         int[] a = new int[] { 9, 20, 3, 16, 6, 5, 7, 1 };
         System.out.println("a[" + a.length + "]=" + Arrays.toString(a));
         System.out.println("find max of a[i]-a[j],i<j : " + findMax(a));
     }

     public static int findMax(int[] a) {
         // 初始化为最小可能的int值
         int max = Integer.MIN_VALUE;
         // a[i]右边元素中的最小值
         int minRight = a[a.length - 1];
         int tempMax;
         for (int i = a.length - 2; i >= 0; i--) {
             tempMax = a[i] - minRight;
             if (a[i] < minRight) {
                 minRight = a[i];
             }
             if (tempMax > max) {
                 max = tempMax;
             }
         }
         return max;
     }
 }