python-Concepts/substring.py at master · Thangarajsubramani/python-Concepts · GitHub

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# find the substring
# 'ABCDGABDE'

def longest_substring(str):

    n = len(str)

    visited = [-1]*256

    visited[ord(str[0])] = 0

    max_len = 1

    current_len = 1

    # char_str=''
    # sub_str=''

    index=0

    # print(visited)

    for i in range(1,n):

        pindex = visited[ord(str[i])]

        if pindex == -1 or (i - current_len > pindex) :
            current_len +=1
            # char_str +=str[i]
        else:

            if current_len > max_len:
                max_len = current_len
                index = i
                # sub_str = char_str
            current_len = 1
            # char_str = str[i]


        visited[ord(str[i])] = i

    # print(visited)

    if current_len > max_len:
        max_len = current_len
        # sub_str = char_str

    substr_index = index-max_len

    return (max_len, str[substr_index:substr_index + max_len] )


# print(longest_substring('BCDBGAFBDEB'))


def repeat_substr(str):

    n = len(str)
    count = 0
    max_len = 0;
    index=0
    for i in range(0, n-1):
        if str[i] == str[i+1]:
            count +=1
        else:
            # print(max_len,count)
            if count > max_len:
                max_len = count
                index=i
                # print(index)

            count =0


    if count > max_len:
       max_len = count
       index = i +1

    print(max_len, count)
    substr = index - max_len
    # print(substr)
    return (max_len+1, str[substr: substr + max_len +1])


print(repeat_substr('abaaabcaaaa'))