<p>Given a string <code>s</code>, return <code>true</code> <em>if the </em><code>s</code><em> can be palindrome after deleting <strong>at most one</strong> character from it</em>.</p>

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

<pre>
<strong>Input:</strong> s = &quot;aba&quot;
<strong>Output:</strong> true
</pre>

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

<pre>
<strong>Input:</strong> s = &quot;abca&quot;
<strong>Output:</strong> true
<strong>Explanation:</strong> You could delete the character &#39;c&#39;.
</pre>

<p><strong class="example">Example 3:</strong></p>

<pre>
<strong>Input:</strong> s = &quot;abc&quot;
<strong>Output:</strong> false
</pre>

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

<ul>
	<li><code>1 &lt;= s.length &lt;= 10<sup>5</sup></code></li>
	<li><code>s</code> consists of lowercase English letters.</li>
</ul>

class Solution {
public:
    /*
    int deletecount = 0;
    bool findout(string str, int i, int j)
    {
        if(i >= j)
            return true;

        if(str[i] == str[j])
            return findout(str, i+1, j-1);
        else
        {
            if (deletecount == 0)
            {
                deletecount = 1;
                return findout(str, i+1, j) || findout(str, i, j-1);
            }
        }
        return false;
    }
    */
    bool validPalindrome(string s) {
        //return findout(s, 0, s.size()-1);
        stack<pair<int, int>> stk;
        int i, j;
        int deleteCount;

        i=0;
        j=s.size()-1;
        deleteCount = 0;
        stk.push(pair<int, int>(i, j));
        while(!stk.empty())
        {
            pair<int, int> pr = stk.top();
            stk.pop();

            i=pr.first;
            j=pr.second;
            while(i<j)
            {
                if(s[i] == s[j])
                {
                    i++;
                    j--;
                }
                else
                {
                    if(deleteCount == 0)
                    {
                        deleteCount = 1;
                        stk.push(pair<int, int>(i+1, j));
                        j--;
                    }
                    else
                    {
                        break;
                    }
                }
            }

            if(i>=j)
                break;
        }

        if(i >= j)
            return true;
        else
            return false;
    }
};
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