MIT 6.00 Assignments solution

ps3b.py

#!/usr/bin/env python
# -*- coding: utf-8 -*-


def subStringMatchExact(target, key):
    idx = 0
    res = ()
    while True:
        new_idx = target.find(key, idx)
        if new_idx < 0:
            return res
        else:
            idx = new_idx + 1
            res += (new_idx, )


# This recursive solution is incorrect!
# the answer is (5, 9) which 9 should plus 5 + 1 for the correct answer
#
# def subStringMatchExactRecursive(target, key):
#     new_idx = target.find(key)
#     if new_idx < 0:
#         return ()
#     else:
#         return (new_idx, ) + subStringMatchExactRecursive(target[new_idx + 1:], key)


print(subStringMatchExact("atgacatgcacaagtatgcat", "atgc"))