<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 {
private:
    int save[100001][2][2];

    int isPalindrome(const string &s, int ind, bool skipLeft, bool skipRight) {
        int leftIndex = ind + skipLeft; // validate
        int rightIndex = s.size() - 1 - ind - skipRight; // validate

        if (leftIndex >= rightIndex) return true;

        auto &saveVal = save[ind][skipLeft][skipRight];
        if (saveVal != -1) return saveVal;

        if (s[leftIndex] == s[rightIndex]) {
            return saveVal = isPalindrome(s, ind + 1, skipLeft, skipRight);

        } else {
            if (skipLeft || skipRight) return saveVal = false;
            
            bool shouldSkipLeft = isPalindrome(s, ind, true, false);
            if (shouldSkipLeft) return saveVal = true;

            return saveVal = isPalindrome(s, ind, false, true);
        }
    }

    int isPalindrome(const string &s, int start, int end) {
        while (start < end) {
            if (s[start] != s[end]) return false;
            
            start++;
            end--;
        }
        return true;
    }

public:
    bool validPalindrome(string s) {
        /*for (int i = 0; i < s.length(); i++) {
            for (int j = 0; j < 2; j++) {
                for (int z = 0; z < 2; z++) {
                    save[i][j][z] = -1;
                }
            }
        }

        return isPalindrome(s, 0, false, false);*/
        int start = 0;
        int end = s.size() - 1;

        while (start < end) {
            if (s[start] != s[end]) return isPalindrome(s, start + 1, end) || isPalindrome(s, start, end - 1);
            
            start++;
            end--;
        }

        return true;
    }
};
20500