Problem_665. Non decreasing Array - xwu36/LeetCode GitHub Wiki

Problem:

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].

Code:

class Solution {
     public boolean checkPossibility(int[] nums) {
        if(nums == null || nums.length == 0)
            return true;
         int n = nums.length;
         int count = 0;
         for(int i = 1; i < n; i++){
            if(nums[i] < nums[i - 1]){
                count++;
                if(count > 1) return false;
                if(i < 2 || nums[i - 2] <= nums[i]) nums[i - 1] = nums[i];
                else nums[i] = nums[i - 1];
            } 
         }
         return true;
    }
}