题解 | #机器人的运动范围#

package main

func digitalSum(num int) int{
    var sum int
    for num > 0 {
        sum += num % 10
        num /= 10
    }
    return sum
}

func dfs(threshold int, rows int, cols int, x int, y int, isVisited [][]bool) int {
    if x < 0 || y < 0 || x >= rows || y >= cols || isVisited[x][y] || digitalSum(x) + digitalSum(y) > threshold {
           return 0
    }
    isVisited[x][y] = true
    return 1 + dfs(threshold, rows, cols, x - 1, y, isVisited) + dfs(threshold, rows, cols, x + 1, y, isVisited) + dfs(threshold, rows, cols, x, y - 1, isVisited) + dfs(threshold, rows, cols, x, y + 1, isVisited)
}

func movingCount(threshold int, rows int, cols int) int {
    if threshold < 0 || rows <= 0 || cols <= 0 {
        return 0
    }
    isVisited := make([][]bool, rows)
    for i := 0; i < rows; i ++ {
        isVisited[i] = make([]bool, cols)
    }
    return dfs(threshold, rows, cols, 0, 0, isVisited)
}