var dx []int = []int{1, 0, -1, 0}
var dy []int = []int{0, -1, 0, 1}

func pacificAtlantic(matrix [][]int) (res [][]int) {
	m, n := len(matrix), len(matrix[0])
	ocean := make([][]int, m)
	for i := 0; i < m; i++ {
		ocean[i] = make([]int, n)
	}
	for i := 0; i < m; i++ { // b10: pacific, b01: atlantic
		ocean[i][0] |= 2
		ocean[i][n-1] |= 1
	}
	for i := 0; i < n; i++ {
		ocean[0][i] |= 2
		ocean[m-1][i] |= 1
	}
	dfs(matrix, 0, 0, ocean)
	for i := 0; i < m; i++ {
		for j := 0; j < m; j++ {
			if ocean[i][j] == 3 {
				res = append(res, []int{j, i})
			}
		}
	}
	return
}

func dfs(matrix [][]int, x, y int, ocean [][]int) {
	
}