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;

     }

 }