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

<p>We define an array is non-decreasing if <code>nums[i] &lt;= nums[i + 1]</code> holds for every <code>i</code> (<strong>0-based</strong>) such that (<code>0 &lt;= i &lt;= n - 2</code>).</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

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

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> nums = [4,2,1]
<strong>Output:</strong> false
<strong>Explanation:</strong> You cannot get a non-decreasing array by modifying at most one element.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>n == nums.length</code></li>
	<li><code>1 &lt;= n &lt;= 10<sup>4</sup></code></li>
	<li><code>-10<sup>5</sup> &lt;= nums[i] &lt;= 10<sup>5</sup></code></li>
</ul>

class Solution {
public:
    bool check(vector<int> &nums, int ind)
    {
        int n=nums.size();
        if(ind==0)
        {
            for(int i=2; i<n; i++)
                if(nums[i]<nums[i-1])
                    return false;
        }
        else if(ind==n-1)
        {
            for(int i=1; i<n-1; i++)
                if(nums[i]<nums[i-1])
                    return false;
        }
        else
        {
            for(int i=1; i<n; i++)
            {
                if(i==ind)
                    continue;
                if(i-1==ind)
                {
                    if(nums[i]<nums[i-2])
                        return false;
                }
                else if(nums[i]<nums[i-1])
                    return false;
            }
        }
        return true;
    }
    bool checkPossibility(vector<int>& nums) 
    {
        int n=nums.size();
        if(n<=2)
            return true;
        for(int i=0; i<n; i++)
            if(check(nums, i))
                return true;
        return false;
    }
};
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