【python-leetcode329-深度优先搜索】矩阵中的最长递增路径

class Solution:
    def longestIncreasingPath(self, matrix):
        if not matrix:
            return 0
        row_n = len(matrix)
        col_n = len(matrix[0])
        res = 1
        resut_save = [[0 for _ in range(col_n)] for _ in range(row_n)]
        for i in range(row_n):
            for j in range(col_n):
                res = max(res, self.dfs(matrix, i, j, resut_save))
        return res
    def dfs(self,matrix, i, j, resut_save):
        if resut_save[i][j] != 0:
            return  resut_save[i][j]
        dirctions = [(1, 0), (-1, 0), (0, 1), (0, -1)]
        res = 1
        for dx, dy in dirctions:
            x = i + dx
            y = j + dy
            if 0<= x < len(matrix) and 0<= y < len(matrix[0]) and matrix[x][y] > matrix[i][j]:
                res = max(res, self.dfs(matrix, x, y, resut_save) + 1)
        resut_save[i][j] = res
        return res

s=Solution()
res=s.longestIncreasingPath([[9,9,4],[6,6,8],[2,1,1]])
print(res)