字符串

滑动窗口

字符串匹配问题

字符串翻转问题

字符串字符分割

def expend(s):
    i = 0
    arr = []
    temp = []
    while i < len(s):
        # 开始一组
        if s[i] == "{":
            # 保存上一组
            if temp:
                arr.append(temp[:])
                temp = []
            while s[i] != "}":
                if s[i].isalpha():
                    temp.append(s[i])
                i += 1
            arr.append(temp[:])
            temp = []
            i += 1

        elif s[i].isalpha():
            temp.append(s[i])
            i += 1

    if temp:
        arr.append(temp[:])

    return arr

def split(str, flag=" "):
    r, l = 0, 0
    res = []
    while r < len(str):
        if str[r] == ' ':
            res.append(str[l:r])
            l = r + 1
        elif r == len(str)-1:
            res.append(str[l:])
        r += 1
        
    return res

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