MIT 6.00 Assignments soluntion

ps3a.py

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


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


def countSubStringMatchRecursive(target, key):
    new_idx = target.find(key)
    if new_idx < 0:
        return 0
    else:
        return countSubStringMatchRecursive(target[new_idx + 1:], key) + 1


print(countSubStringMatch("atgacatgcacaagtatgcat", "atgc"))