反转、旋转与翻转

• 非原地：一维用切片，二维用list(map(list, zip(*matrix)))格式
• 原地：一维反转 - 前后交换，二维旋转 - 对角线翻转交换之后再进行一维反转
  python中字符串不可变，无法原地

class ReverseInSitu:
    """
    反转/旋转
    """
    # 反转字符串(python字符串不可变，故不能原地反转)
    @staticmethod
    def reverse_str(chars: str) -> str:
        if not chars:
            return
        return chars[::-1]

    # 按单词反转字符串(python字符串不可变，故不能原地反转)
    def reverse_str_by_word(self, chars: str) -> str:
        if not chars:
            return
        chars_list = self.reverse_str(chars).split()
        res = []
        for s in chars_list:
            res.append(self.reverse_str(s))
        return ' '.join(res)

    # 顺时针旋转任意二维矩阵（非原地）
    @staticmethod
    def rotate_any_matrix_clockwise_90(matrix: list) -> list:
        if not matrix:
            return
        m, n = len(matrix), len(matrix[0])
        try:
            for i in range(m):
                assert len(matrix[i]) == n      # 必须是矩阵
        except AssertionError:
            raise
        return list(map(list, zip(*matrix[::-1])))  # list(map(list, zip(*matrix)))，就是\翻转

    # 逆时针旋转任意二维矩阵（非原地）
    def rotate_any_matrix_anti_clockwise_90(self, matrix: list) -> list:
        if not matrix:
            return
        m, n = len(matrix), len(matrix[0])
        try:
            for i in range(m):
                assert len(matrix[i]) == n      # 必须是矩阵
        except AssertionError:
            raise
        for i in range(m):
            self.reverse_list(matrix[i])
        return list(map(list, zip(*matrix)))  # list(map(list, zip(*matrix[::-1])))，就是/翻转

    # 原地反转一维数组
    @staticmethod
    def reverse_list(arr: list) -> None:
        if not arr:
            return
        i, j = 0, len(arr)-1
        while i < j:
            arr[i], arr[j] = arr[j], arr[i]
            i += 1
            j -= 1

    # 原地顺时针旋转二维矩阵90度
    def rotate_matrix_clockwise_90(self, matrix: list) -> None:
        if not matrix:
            return
        n = len(matrix)
        try:
            for i in range(n):
                assert len(matrix[i]) == n    # 原地旋转必须行列数相等
        except AssertionError:
            raise
        for i in range(n):  # 沿\对角线翻转
            for j in range(i, n):
                matrix[i][j], matrix[j][i] = matrix[j][i], matrix[i][j]
        for i in range(n):  # 反转每行
            self.reverse_list(matrix[i])

    # 原地逆时针旋转二维矩阵90度
    def rotate_matrix_anti_clockwise_90(self, matrix: list) -> None:
        if not matrix:
            return
        n = len(matrix)
        try:
            for i in range(n):
                assert len(matrix[i]) == n    # 原地旋转必须行列数相等
        except AssertionError:
            raise
        for i in range(n):  # 沿/对角线翻转
            for j in range(n-i):
                matrix[i][j], matrix[n-j-1][n-i-1] = matrix[n-j-1][n-i-1], matrix[i][j]
        for i in range(n):  # 反转每行
            self.reverse_list(matrix[i])


if __name__ == '__main__':
    rs = ReverseInSitu()
    matrix_1 = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
    rs.rotate_matrix_clockwise_90(matrix_1)
    print(matrix_1)
    matrix_2 = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12], [13, 14, 15, 16]]
    rs.rotate_matrix_anti_clockwise_90(matrix_2)
    print(matrix_2)
    matrix_3 = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
    print(rs.rotate_any_matrix_clockwise_90(matrix_3))
    matrix_4 = [[1, 2, 3, 4], [5, 6, 7, 8], [9, 10, 11, 12]]
    print(rs.rotate_any_matrix_anti_clockwise_90(matrix_4))
    str_1 = 'abc def gh'
    print(rs.reverse_str(str_1))
    str_2 = 'abc def gh'
    print(rs.reverse_str_by_word(str_2))

标签：return,matrix,反转,list,len,旋转,range,str,翻转
来源： https://www.cnblogs.com/daxiacet/p/16382912.html