Leetcode: Out of Boundary Paths

Out of Boundary Paths

Similar Problems:

There is an m by n grid with a ball. Given the start coordinate (i,j) of the ball, you can move the ball to adjacent cell or cross the grid boundary in four directions (up, down, left, right). However, you can at most move N times. Find out the number of paths to move the ball out of grid boundary. The answer may be very large, return it after mod 109 + 7.

Example 1:

Input: m = 2, n = 2, N = 2, i = 0, j = 0
Output: 6

Out of Boundary Paths

Example 2:

Input: m = 1, n = 3, N = 3, i = 0, j = 1
Output: 12

Out of Boundary Paths


  1. Once you move the ball out of boundary, you cannot move it back.
  2. The length and height of the grid is in range [1,50].
  3. N is in range [0,50].

Github: code.dennyzhang.com

Credits To: leetcode.com

Leave me comments, if you have better ways to solve.

  • Solution: XXX

General Thinkings:

Key Observations:

Walk Through Testdata

// Blog link: https://code.dennyzhang.com/out-of-boundary-paths


Share It, If You Like It.

Leave a Reply

Your email address will not be published.