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  • Description

    Given a string S of length N, the task is to find the length of the longest palindromic substring from a given string.

    Examples:

    Input: S = “abcbab” Output: 5 Explanation: string “abcba” is the longest substring that is a palindrome which is of length 5.

    Input: S = “abcdaa” Output: 2 Explanation: string “aa” is the longest substring that is a palindrome which is of length 2.

    Note: If the string is empty or None or null then just return 0.do not try to convert the string to lowercase

    Code 
    def length_longest_palindrome(string):
    n = len(string) 
    if n == 0:
        return 0 
    
    maxlen = 1
    table = [[False for i in range(n)]for j in range(n)] 
    for i in range(n):
        table[i][i] = True
        
    start = 0 
    for i in range(n-1):
        if string[i] == string[i+1]:
            table[i][i+1] = True 
            start = i 
            maxlen = 2 
            
    for k in range(3,n+1):
        for i in range(n-k+1):
            j = i + k - 1 
            if table[i+1][j-1] and string[i] == string[j]:
                table[i][j] = True
                
                if k > maxlen:
                    start = i 
                    maxlen = k 
    return maxlen
    Test Cases 
    import codewars_test as test
# TODO Write tests
import solution # or from solution import example

# test.assert_equals(actual, expected, [optional] message)
@test.describe("Example")
def test_group():
    @test.it("test case")
    def test_case():
        test.assert_equals(length_longest_palindrome(''),0)
        test.assert_equals(length_longest_palindrome('a'),1)
        test.assert_equals(length_longest_palindrome('aaabbaa'),6)
        test.assert_equals(length_longest_palindrome('Hannah'),4)
        test.assert_equals(length_longest_palindrome('geeks'),2) 
        test.assert_equals(length_longest_palindrome('forgeeksskeegfor'),10)
        test.assert_equals(length_longest_palindrome('aab'),2)
        test.assert_equals(length_longest_palindrome('Abbas'),2)
    View Run Output