2837. Minimum Operations to Make the Integer Zero

Medium
Bit Manipulation
Brainteaser
Enumeration

Description

You are given two integers num1 and num2.

In one operation, you can choose integer i in the range [0, 60] and subtract 2i + num2 from num1.

Return the integer denoting the minimum number of operations needed to make num1 equal to 0.

If it is impossible to make num1 equal to 0, return -1.

 

Example 1:

Input: num1 = 3, num2 = -2
Output: 3
Explanation: We can make 3 equal to 0 with the following operations:
- We choose i = 2 and subtract 22 + (-2) from 3, 3 - (4 + (-2)) = 1.
- We choose i = 2 and subtract 22 + (-2) from 1, 1 - (4 + (-2)) = -1.
- We choose i = 0 and subtract 20 + (-2) from -1, (-1) - (1 + (-2)) = 0.
It can be proven, that 3 is the minimum number of operations that we need to perform.

Example 2:

Input: num1 = 5, num2 = 7
Output: -1
Explanation: It can be proven, that it is impossible to make 5 equal to 0 with the given operation.

 

Constraints:

  • 1 <= num1 <= 109
  • -109 <= num2 <= 109

Hints

Hint 1
If we want to make integer n equal to 0 by only subtracting powers of 2 from n, in how many operations can we achieve it?
Hint 2
We need at least - the number of bits in the binary representation of n, and at most - n.
Hint 3
Notice that, if it is possible to make num1 equal to 0, then we need at most 60 operations.
Hint 4
Iterate on the number of operations.

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