Spiral Matrix

题目大意

将一个矩阵中的内容螺旋输出。
注意点：

矩阵不一定是正方形
例子：

输入: matrix = [ [1, 2, 3], [4, 5, 6], [7, 8, 9] ]
输出: [1, 2, 3, 6, 9, 8, 7, 4, 5]

解题思路

看代码就可以理解
注意：

while True：
然后里面自行判断结束

代码

class Solution(object):
    def spiralOrder(self, matrix):
        """ :type matrix: List[List[int]] :rtype: List[int] """
        if not matrix: 
            return []
        up = 0
        left = 0
        down = len(matrix)-1
        right = len(matrix[0])-1
        direct = 0  # 0: go right 1: go down 2: go left 3: go up
        res = []
        while True:
            if direct == 0:
                for i in range(left, right+1):
                    res.append(matrix[up][i])
                up += 1
            if direct == 1:
                for i in range(up, down+1):
                    res.append(matrix[i][right])
                right -= 1
            if direct == 2:
                for i in range(right, left-1, -1):
                    res.append(matrix[down][i])
                down -= 1
            if direct == 3:
                for i in range(down, up-1, -1):
                    res.append(matrix[i][left])
                left += 1
            if up > down or left > right: 
                return res
            direct = (direct+1) % 4

Spiral Matrix II

题目大意

将一个正方形矩阵螺旋着填满递增的数字。

解题思路

螺旋填满数字

代码

class Solution(object):
    def generateMatrix(self, n):
        """ :type n: int :rtype: List[List[int]] """
        if n == 0: 
            return []
        matrix = [[0 for i in range(n)] for j in range(n)]  # 创建矩阵
        up = 0
        down = len(matrix)-1
        left = 0
        right = len(matrix[0])-1
        direct = 0
        count = 0
        while True:
            if direct == 0:
                for i in range(left, right+1):
                    count += 1; matrix[up][i] = count
                up += 1
            if direct == 1:
                for i in range(up, down+1):
                    count += 1; matrix[i][right] = count
                right -= 1
            if direct == 2:
                for i in range(right, left-1, -1):
                    count += 1; matrix[down][i] = count
                down -= 1
            if direct == 3:
                for i in range(down, up-1, -1):
                    count += 1; matrix[i][left] = count
                left += 1
            if count == n*n: 
                return matrix
            direct = (direct+1) % 4

总结