63. 不同路径 II(Medium)

Go 示例

func uniquePathsWithObstacles(obstacleGrid [][]int) int {
    if len(obstacleGrid) == 0 || len(obstacleGrid[0]) == 0 { // 空
        return 0
    }
    n, m := len(obstacleGrid), len(obstacleGrid[0]) // 终点有障碍
    if obstacleGrid[n - 1][m - 1] == 1 {
        return 0
    }
    dp := make([][]int, n) // 初始化数组
    for i:= 0; i < n; i++ {
        dp[i] = make([]int, m)
    }
    for i:= 0; i < n; i++ {
        if obstacleGrid[i][0] == 1 {
            break
        }
        dp[i][0] = 1
    }
    for i:= 0; i < m; i++ {
        if obstacleGrid[0][i] == 1 {
            break
        }
        dp[0][i] = 1
    }

    for i := 1; i < n; i++ {
        for j := 1; j < m; j++ {
            if obstacleGrid[i][j] == 0 {
                dp[i][j] = dp[i - 1][j] + dp[i][j - 1] 
            }
        }
    }
    
    return dp[n - 1][m - 1]
}