A robot is located at the top-left corner of a m x n grid (marked ‘Start’ in the diagram below).
The robot can only move either down or right at any point in time. The robot is trying to reach the bottom-right corner of the grid (marked ‘Finish’ in the diagram below).
How many possible unique paths are there? Above is a grid. How many possible unique paths are there?
Note: m and n will be at most 100.
Result: Accepted Time: 48 ms
Here should be some explanations.
class Solution(object): def uniquePaths(self, m, n): """ :type m: int :type n: int :rtype: int """ sum = m + n - 2; # c(sum,n-1) = sum!/(n-1)!(m-1)! if m < n: m,n = n,m ans = 1; n = 1; while m <= sum: ans *=m ans /= n m += 1 n += 1 return ans
- Time Complexity:
- Space Complexity: