# Length of the longest substring that do not contain any palindrome

Given a string of lowercase, find the length of the longest substring that does not contain any palindrome as a substring.

Examples:

```Input : str = "daiict"
Output : 3
dai, ict are longest substring that do not contain any
palindrome as substring

Input : str = "a"
Output : 0
a is itself a palindrome ```

The idea is to observe that if any character forms a palindrome, it can not be included in any substring. So, in that case, the required substring will be picked from before or after that character which forms a palindrome.
Therefore, a simple solution is to traverse the string and, for each character, check whether it forms a palindrome of length 2 or 3 with its adjacent characters. If it does not, then increase the length of the substring, otherwise re-initialize the length of the substring to zero. Using this approach, find the length of the maximum substring.

Below is the implementation of the above approach:

## C++

 `// C++ implementation of the above approach`   `#include ` `using` `namespace` `std;`   `// Function to find the length of the longest` `// substring` `int` `lenoflongestnonpalindrome(string s)` `{` `    ``// initializing the variables` `    ``int` `max1 = 1, len = 0;`   `    ``for` `(``int` `i = 0; i < s.length() - 1; i++) {` `        ``// checking palindrome of size 2` `        ``// example: aa` `        ``if` `(s[i] == s[i + 1])` `            ``len = 0;` `        ``// checking palindrome of size 3` `        ``// example: aba` `        ``else` `if` `(s[i + 1] == s[i - 1] && i > 0)` `            ``len = 1;` `        ``else` `// incrementing length of substring` `            ``len++;` `        ``max1 = max(max1, len + 1); ``// finding maximum` `    ``}`   `    ``// if there exists single character then` `    ``// it is always palindrome` `    ``if` `(max1 == 1)` `        ``return` `0;` `    ``else` `        ``return` `max1;` `}`   `// Driver Code` `int` `main()` `{` `    ``string s = ``"synapse"``;` `    ``cout << lenoflongestnonpalindrome(s) << ``"\n"``;` `    ``return` `0;` `}`

## Java

 `// Java implementation of the above approach` `import` `java.util.Arrays;` `import` `java.lang.Math;`   `class` `GFG {`   `    ``// Function to find the length of the longest` `    ``// substring` `    ``public` `static` `int` `lenoflongestnonpalindrome(String s)` `    ``{` `        ``// initializing the variables` `        ``int` `max1 = ``1``, len = ``0``;` `        ``char``[] new_str = s.toCharArray();`   `        ``for` `(``int` `i = ``0``; i < new_str.length - ``1``; i++) {` `            ``// checking palindrome of size 2` `            ``// example: aa` `            ``if` `(new_str[i] == new_str[i + ``1``])` `                ``len = ``0``;` `            ``// checking palindrome of size 3` `            ``// example: aba` `            ``else` `if` `(i > ``0` `&& (new_str[i + ``1``] == new_str[i - ``1``]))` `                ``len = ``1``;` `            ``else` `// incrementing length of substring` `                ``len++;` `            ``max1 = Math.max(max1, len + ``1``); ``// finding maximum` `        ``}`   `        ``// if there exits single character then` `        ``// it is always palindrome` `        ``if` `(max1 == ``1``)` `            ``return` `0``;` `        ``else` `            ``return` `max1;` `    ``}`   `    ``// Driver Code` `    ``public` `static` `void` `main(String[] args)` `    ``{` `        ``String s = ``"synapse"``;` `        ``System.out.println(lenoflongestnonpalindrome(s));` `    ``}` `}`   `// This code is contributed by princiraj1992`

## Python3

 `# Python3 implementation of the above approach `   `# Function to find the length ` `# of the longest substring ` `def` `lenoflongestnonpalindrome(s): `   `    ``# initializing the variables ` `    ``max1, length ``=` `1``, ``0`   `    ``for` `i ``in` `range``(``0``, ``len``(s) ``-` `1``): ` `        `  `        ``# checking palindrome of ` `        ``# size 2 example: aa ` `        ``if` `s[i] ``=``=` `s[i ``+` `1``]: ` `            ``length ``=` `0` `            `  `        ``# checking palindrome of ` `        ``# size 3 example: aba ` `        ``elif` `s[i ``+` `1``] ``=``=` `s[i ``-` `1``] ``and` `i > ``0``:` `            ``length ``=` `1` `        ``else``: ``# incrementing length of substring ` `            ``length ``+``=` `1` `        ``max1 ``=` `max``(max1, length ``+` `1``) ``# finding maximum `   `    ``# If there exits single character ` `    ``# then it is always palindrome ` `    ``if` `max1 ``=``=` `1``: ` `        ``return` `0` `    ``else``:` `        ``return` `max1 `   `# Driver Code ` `if` `__name__ ``=``=` `"__main__"``:`   `    ``s ``=` `"synapse"` `    ``print``(lenoflongestnonpalindrome(s))` `    `  `# This code is contributed by Rituraj Jain`

## C#

 `// C# implementation of the above approach ` `using` `System;` `    `  `class` `GFG ` `{`   `    ``// Function to find the length of the longest` `    ``// substring` `    ``public` `static` `int` `lenoflongestnonpalindrome(String s)` `    ``{` `        ``// initializing the variables` `        ``int` `max1 = 1, len = 0;` `        ``char``[] new_str = s.ToCharArray();`   `        ``for` `(``int` `i = 0; i < new_str.Length - 1; i++) ` `        ``{` `            ``// checking palindrome of size 2` `            ``// example: aa` `            ``if` `(new_str[i] == new_str[i + 1])` `                ``len = 0;` `                `  `            ``// checking palindrome of size 3` `            ``// example: aba` `            ``else` `if` `(i > 0 && (new_str[i + 1] == new_str[i - 1]))` `                ``len = 1;` `            ``else` `// incrementing length of substring` `                ``len++;` `            ``max1 = Math.Max(max1, len + 1); ``// finding maximum` `        ``}`   `        ``// if there exits single character then` `        ``// it is always palindrome` `        ``if` `(max1 == 1)` `            ``return` `0;` `        ``else` `            ``return` `max1;` `    ``}`   `    ``// Driver Code` `    ``public` `static` `void` `Main(String[] args)` `    ``{` `        ``String s = ``"synapse"``;` `        ``Console.WriteLine(lenoflongestnonpalindrome(s));` `    ``}` `}`   `// This code has been contributed by 29AjayKumar`

## PHP

 ` 0) ` `            ``\$len` `= 1; ` `        ``else` `// incrementing length of substring ` `            ``\$len``++; ` `        ``\$max1` `= max(``\$max1``, ``\$len` `+ 1); ``// finding maximum ` `    ``} `   `    ``// if there exits single character then ` `    ``// it is always palindrome ` `    ``if` `(``\$max1` `== 1) ` `        ``return` `0; ` `    ``else` `        ``return` `\$max1``; ` `} `   `// Driver Code ` `\$s` `= ``"synapse"``; ` `echo` `lenoflongestnonpalindrome(``\$s``), ``"\n"``; `   `// This code is contributed by AnkitRai01`   `?>`

## Javascript

 ``

Output:

`7`

Time complexity: O(n) where n is length of input string

Auxiliary Space: O(1)

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