标签：Difference min int res nums Maximum maximum difference 2016

原题链接在这里：https://leetcode.com/problems/maximum-difference-between-increasing-elements/

题目：

Given a 0-indexed integer array nums of size n, find the maximum difference between nums[i] and nums[j] (i.e., nums[j] - nums[i]), such that 0 <= i < j < n and nums[i] < nums[j].

Return the maximum difference. If no such i and j exists, return -1.

Example 1:

Input: nums = [7,1,5,4]
Output: 4
Explanation:
The maximum difference occurs with i = 1 and j = 2, nums[j] - nums[i] = 5 - 1 = 4.
Note that with i = 1 and j = 0, the difference nums[j] - nums[i] = 7 - 1 = 6, but i > j, so it is not valid.

Example 2:

Input: nums = [9,4,3,2]
Output: -1
Explanation:
There is no i and j such that i < j and nums[i] < nums[j].

Example 3:

Input: nums = [1,5,2,10]
Output: 9
Explanation:
The maximum difference occurs with i = 0 and j = 3, nums[j] - nums[i] = 10 - 1 = 9. 

Constraints:

• n == nums.length
• 2 <= n <= 1000
• 1 <= nums[i] <= 109

题解：

Update the min when encountering num in nums.

Update maxDiff with num - min.

Note: If nums keep decreasing or equal, then maxDiff should be -1. 

If there are equal in decreasing, then res = 0, thus return res == 0 ? -1 : res.

Time Complexity: O(n). n = nums.length.

Space: O(1).

AC Java:

 1 class Solution {
 2     public int maximumDifference(int[] nums) {
 3         if(nums == null || nums.length < 2){
 4             return -1;
 5         }
 6         
 7         int n = nums.length;
 8         int res = -1;
 9         int min = nums[0];
10         for(int i = 1; i < n; i++){
11             res = Math.max(res, nums[i] - min);
12             min = Math.min(min, nums[i]);
13         }
14         
15         return res == 0 ? -1 : res;
16     }
17 }

类似Best Time to Buy and Sell Stock.

标签：Difference,min,int,res,nums,Maximum,maximum,difference,2016
来源： https://www.cnblogs.com/Dylan-Java-NYC/p/16437202.html

本站声明： 1. iCode9 技术分享网（下文简称本站）提供的所有内容，仅供技术学习、探讨和分享；
2. 关于本站的所有留言、评论、转载及引用，纯属内容发起人的个人观点，与本站观点和立场无关；
3. 关于本站的所有言论和文字，纯属内容发起人的个人观点，与本站观点和立场无关；
4. 本站文章均是网友提供，不完全保证技术分享内容的完整性、准确性、时效性、风险性和版权归属；如您发现该文章侵犯了您的权益，可联系我们第一时间进行删除；
5. 本站为非盈利性的个人网站，所有内容不会用来进行牟利，也不会利用任何形式的广告来间接获益，纯粹是为了广大技术爱好者提供技术内容和技术思想的分享性交流网站。