Unique Paths II

Medium

Company Tags

You are given an m x n integer array grid. There is a robot initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-right corner (i.e., grid[m - 1][n - 1]). The robot can only move either down or right at any point in time.

An obstacle and space are marked as 1 or 0 respectively in grid. A path that the robot takes cannot include any square that is an obstacle.

Return the number of possible unique paths that the robot can take to reach the bottom-right corner.

The testcases are generated so that the answer will be less than or equal to 2 * (10^9).

Example 1:

Input: obstacleGrid = [[0,0,0],[0,0,0],[0,1,0]]

Output: 3

Explanation: There are three ways to reach the bottom-right corner:

  1. Right -> Right -> Down -> Down
  2. Right -> Down -> Right -> Down
  3. Down -> Right -> Right -> Down

Example 2:

Input: obstacleGrid = [[0,0,0],[0,0,1],[0,1,0]]

Output: 0

Constraints:

  • m == obstacleGrid.length
  • n == obstacleGrid[i].length
  • 1 <= m, n <= 100
  • obstacleGrid[i][j] is 0 or 1.


Company Tags

Please upgrade to NeetCode Pro to view company tags.

obstacleGrid =