Advent of Code 2021, Day 9
code func lowest(i, j int) { direction := [][]int{{0, -1}, {0, 1}, {-1, 0}, {1, 0}} for _, v := range direction { if v[0]+i < 0 || v[1]+j < 0 || v[0]+i >= len(matrix) || v[1]+j >= len(matrix[0]) { continue } if matrix[i][j] > matrix[i+v[0]][j+v[1]] { tracker[i+v[0]][j+v[1]] = FLAG tracker[i][j] = 0 lowest(i+v[0], j+v[1]) } } }