# Non-Decreasing Array Problem

## Description

LeetCode Problem 665.

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

We define an array is non-decreasing if nums[i] <= nums[i + 1] holds for every i (0-based) such that (0 <= i <= n - 2).

Example 1:

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

Example 2:

``````1
2
3
Input: nums = [4,2,1]
Output: false
Explanation: You can't get a non-decreasing array by modify at most one element.
``````

Constraints:

• n == nums.length
• 1 <= n <= 10^4
• -10^5 <= nums[i] <= 10^5

## Sample C++ Code

``````1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
class Solution {
public:
bool checkPossibility(vector<int>& nums) {
for (int i = 0; i < nums.size() - 1; i++) {
if (nums[i] > nums[i + 1]) {
if (i - 1 >= 0 && nums[i - 1] > nums[i + 1])
nums[i + 1] = nums[i];
else
nums[i] = nums[i + 1];
break;
}
}
for (int i = 0; i < nums.size() - 1; i++) {
if (nums[i] > nums[i + 1])
return false;
}
return true;
}
};
``````