Program to find number of given operations required to reach Target in Python

Suppose we have two values start and end, we have to find the minimum number of operations needed to convert start to end by using these operations −

• Decrement by 1

• Multiply by 2

So, if the input is like start = 2, end = 7, then the output will be 3, as we can multiply 2 to get 4, then multiply 2 to get 8 and then subtract 1 to get 7.

To solve this, we will follow these steps −

• ans := 0

• Do the following infinitely, do

  • if end <= start, then

    • return ans + start − end

  • otherwise when end is odd, then

    • end := end + 1, ans := ans + 1

  • otherwise,

    • end := quotient of end / 2

    • ans := ans + 1

Let us see the following implementation to get better understanding −

Example

 Live Demo

class Solution:
   def solve(self, start, end):
      ans = 0
      while True:
         if end <= start:
            return ans + start - end
         elif end % 2:
            end += 1
            ans += 1
         else:
            end //= 2
            ans += 1
ob1 = Solution()
start = 2
end = 7
print(ob1.solve(start, end))

Input

2, 7

Output

3

Arnab Chakraborty

Updated on: 21-Oct-2020

304 Views

Kickstart Your Career

Get certified by completing the course

Get Started