class Solution(object):
    def pacificAtlantic(self, matrix):
        """
        :type matrix: List[List[int]]
        :rtype: List[List[int]]
        """
        def dfs(i, j, visited):
            if not visited[i][j]:
                print i, j
                for row in visited:
                    print row
                for x, y in ((0,1),(1,0),(-1,0),(0,-1)):
                    x_coord, y_coord = x + i, j + y
                    if 0<=x_coord<m and 0<=y_coord<n:
                        if matrix[x_coord][y_coord] >= matrix[i][j]:
                            dfs(x_coord,y_coord,visited)

        if not matrix or not matrix[0]:
            return [[]]

        m, n = len(matrix), len(matrix[0])

        p = [[False] * n] * m
        a = [[False] * n] * m

        #for row in p:
        #    print row

        dfs(0,0,p)

        #for row in p:
        #    print row

        #for i in range(m):
        #    dfs(i, 0, p)
        #    dfs(i, n-1, a)

        #for j in range(n):
        #    dfs(0, j, p)
        #    dfs(m-1, j, a)

        #return [(i,j) for i in range(m) for j in range(n) if a[i][j] and p[i][j]]