View difference between Paste ID: 7hbFPTgp and wvVm1NuA

 # from math import factorial as f
 class Solution:
 	# @param A : integer
 	# @param B : integer
 	# @return an integer
 
 	hmap = {0:1, 1:1}
 	def factorial(self, n):
         if n not in self.hmap:
             ans = n * self.factorial(n-1)
             self.hmap[n] = ans
         return self.hmap[n]
 
     # def countPaths(self, X, Y, x, y):
     #     if x == X-1 and y == Y-1:
     #         return 1
     #     elif x == X-1:
     #         return self.countPaths(X, Y, x, y+1)
     #     elif y == Y-1:
     #         return self.countPaths(X, Y, x+1, y)
     #     else:
     #         return self.countPaths(X, Y, x+1, y) + self.countPaths(X, Y, x, y+1)
 
     # def countPaths(self, x, y):
     #     if x == 1 or y == 1:
     #         return 1
     #     else:
     #         return self.countPaths(x-1, y) + self.countPaths(x, y-1)
 
 
 	def uniquePaths(self, A, B):
 	   # return self.countPaths(A, B, 0, 0)
 	   #hmap = {0:1, 1:1}
 	   ##return self.countPaths(A, B)
 	   #x = min(A, B)-1
 	   #y = max(B, A)-1
 	   #xf = self.factorial(x)
 	   #yf = self.factorial(y)
 	   #return self.factorial(x+y)//(xf*yf)
 
         total = A + B - 2
         smaller = min(A - 1, B - 1)
         nom = 1
         den = 1
         for i in range(smaller):
             nom *= total - i
             den *= i + 1
         return nom//den
 
 	   # return self.factorial(A+B-2)/((self.factorial(A-1))*(self.factorial(B-1)))
 
 	   #grid = [[1 for x in range(B)] for x in range(A)]
 	   #for r in range(1, A):
 	   #    for c in range(1, B):
 	   #        grid[r][c] = grid[r-1][c] + grid[r][c-1]
 	   #return grid[A-1][B-1]