p665.js

/**
 * 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].


 */

 /**
 * @param {number[]} nums
 * @return {boolean}
 */
var checkPossibility = function(nums) {
  let count = 0
  for(let i=0;i + 1<nums.length;i++){
    if (nums[i] > nums[i + 1]) {
      count++
      if (i > 0 && nums[i + 1] < nums[i - 1]){
        nums[i + 1] = nums[i]
      }else{
        nums[i] = nums[i + 1]
      }
    }
  }
  console.log(nums,count)
  return count <= 1
};


let test = [
  [4,2,3],
  [1,2,3,4,5],
  [1,2,3,2,3],
  [1,3,5,1,2,3],
  [1,3,5,5,3,3],
  [6,5,3],
]
for(let item of test){
  console.log(checkPossibility(item))
}