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# 665. Non-decreasing Array

### Description

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`).

### Constraints

* `n == nums.length`
* `1 <= n <= 104`
* `-105 <= nums[i] <= 105`

### Approach

### Links

* GeeksforGeeks
* [Leetcode](https://leetcode.com/problems/non-decreasing-array/)
* ProgramCreek
* [YouTube](https://youtu.be/KpNPa4tVLrc)

### **Examples**

{% tabs %}
{% tab title="Example 1" %}
**Input:** nums = \[4, 2, 3]

**Output:** true

**Explanation:** You could modify the first 4 to 1 to get a non-decreasing array.
{% endtab %}

{% tab title="Example 2" %}
**Input:** nums = \[4, 2, 1]

**Output:** false

**Explanation:** You can't get a non-decreasing array by modify at most one element.
{% endtab %}
{% endtabs %}

### **Solutions**

{% tabs %}
{% tab title="Solution 1" %}

```java
/**
 * Time complexity : 
 * Space complexity : 
 */

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

{% endtab %}
{% endtabs %}

### **Follow up**

*