[BFS] breadth first search #algorithm

bfs.go

var directions = [4][2]int{{0, 1}, {0, -1}, {-1, 0}, {1, 0}}

func bfs(grid [][]int) {
	var (
		queue  [][]int
		m      = len(grid)
		n      = len(grid[0])
	)

	for len(queue) > 0 {
		for size := len(queue); size > 0; size-- {
			point := queue[0]
			queue = queue[1:]

			for _, dir := range directions {
				nr, nc := point[0]+dir[0], point[1]+dir[1]
				if nr >= 0 && nr < m && nc >= 0 && nc < n && grid[nr][nc] == 0 {
					grid[nr][nc] = 1
					queue = append(queue, []int{nr, nc})
				}
			}
		}
	}
}