Non-decreasing Array

Given an array with n integers, your task is to check if it could become non-decreasing by modifying at most 1 element.

We define an array is non-decreasing if array[i] <= array[i + 1] holds for every i (1 <= i < n).

Example 1:

Input: [4,2,3]
Output: True
Explanation: You could modify the first 4 to 1 to get a non-decreasing array. 

Example 2:

Input: [4,2,1]
Output: False
Explanation: You can't get a non-decreasing array by modify at most one element.

Note: The n belongs to [1, 10,000].

 1 public boolean checkPossibility(int[] nums) {
 2         int cnt = 0;                                                                    //the number of changes
 3         for(int i = 1; i < nums.length && cnt<=1 ; i++){
 4             if(nums[i-1] > nums[i]){
 5                 cnt++;
 6                 if(i-2<0 || nums[i-2] <= nums[i])nums[i-1] = nums[i];                    //modify nums[i-1] of a priority
 7                 else nums[i] = nums[i-1];                                                //have to modify nums[i]
 8             }
 9         }
10         return cnt<=1; 
11     }

 

posted @ 2019-04-29 13:19  北叶青藤  阅读(182)  评论(0编辑  收藏  举报