Largest product of contiguous digits in Python

Suppose we have two numbers num and k, we have to find the largest product of k contiguous digits in num. We have to keep in mind that num is guaranteed to have >= k digits.

So, if the input is like num = 52689762 and k = 4, then the output will be 3024, largest product of 4 consecutive digits is (8*9*7*6) = 3024.

To solve this, we will follow these steps −

• largest := 0
• cand := 1
• while (quotient of num/10)^(k-1) > 0, do
  • digits := (last digit of nums)^k
  • cand := 1
  • while digits > 0, do
    • cand := cand * (digits mod 10)
    • if cand is same as 0, then
      • come out from the loop
    • digits := quotient of digits / 10
  • largest := maximum of largest and cand
  • num := quotient of nums / 10
• return largest

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, num, k):
      largest = 0
      while num // 10 ** (k - 1) > 0:
         digits = num % 10 ** k
         cand = 1
         while digits > 0:
            cand *= digits % 10
            if cand == 0:
               break
               digits //= 10
               largest = max(largest, cand)
               num //= 10
      return largest
ob = Solution()
num = 52689762
k = 4
print(ob.solve(num,k))

Input

52689762, 4

Output

3024