
    Design an algorithm for an adaptive learning platform that analyzes student-submitted text to determine the length of the longest pattern that reads the same forwards and backwards when considering any subset of characters in their original order. The result will be used to automatically adjust the difficulty of subsequent language pattern recognition exercises.
    

    
def lps(str):
    """
    Design an algorithm for an adaptive learning platform that analyzes student-submitted text to determine the length of the longest pattern that reads the same forwards and backwards when considering any subset of characters in their original order. The result will be used to automatically adjust the difficulty of subsequent language pattern recognition exercises.
    

    """
def lps(str):
    """
    Design an algorithm for an adaptive learning platform that analyzes student-submitted text to determine the length of the longest pattern that reads the same forwards and backwards when considering any subset of characters in their original order. The result will be used to automatically adjust the difficulty of subsequent language pattern recognition exercises.
    

    """
    n = len(str)
    L = [[0 for x in range(n)] for x in range(n)]
    for i in range(n):
        L[i][i] = 1
    for cl in range(2, n + 1):
        for i in range(n - cl + 1):
            j = i + cl - 1
            if str[i] == str[j] and cl == 2:
                L[i][j] = 2
            elif str[i] == str[j]:
                L[i][j] = L[i + 1][j - 1] + 2
            else:
                L[i][j] = max(L[i][j - 1], L[i + 1][j])
    return L[0][n - 1]