cpp-flashcards/org/study_deck_02/dsa/bit-manipulation/2220-minimum-bit-flips-to-convert-number.org

#+ANKI_DECK: study_deck_02
* TODO 2220. Minimum Bit Flips to Convert Number :easy:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*2220. Minimum Bit Flips to Convert Number][2220. Minimum Bit Flips to Convert Number]]
:END:

A *bit flip* of a number ~x~ is choosing a bit in the binary representation of ~x~ and *flipping* it from either ~0~ to ~1~ or ~1~ to ~0~.

 - For example, for ~x = 7~, the binary representation is ~111~ and we may choose any bit (including any leading zeros not shown) and flip it. We can flip the first bit from the right to get ~110~, flip the second bit from the right to get ~101~, flip the fifth bit from the right (a leading zero) to get ~10111~, etc.

Given two integers ~start~ and ~goal~, return/ the *minimum* number of *bit flips* to convert /~start~/ to /~goal~.

*Example 1:*


#+begin_src
Input: start = 10, goal = 7
Output: 3
Explanation: The binary representation of 10 and 7 are 1010 and 0111 respectively. We can convert 10 to 7 in 3 steps:
- Flip the first bit from the right: 1010 -> 1011.
- Flip the third bit from the right: 1011 -> 1111.
- Flip the fourth bit from the right: 1111 -> 0111.
It can be shown we cannot convert 10 to 7 in less than 3 steps. Hence, we return 3.
#+end_src


*Example 2:*


#+begin_src
Input: start = 3, goal = 4
Output: 3
Explanation: The binary representation of 3 and 4 are 011 and 100 respectively. We can convert 3 to 4 in 3 steps:
- Flip the first bit from the right: 011 -> 010.
- Flip the second bit from the right: 010 -> 000.
- Flip the third bit from the right: 000 -> 100.
It can be shown we cannot convert 3 to 4 in less than 3 steps. Hence, we return 3.
#+end_src


*Constraints:*

 - ~0 <= start, goal <= 10^{9}~

*Note:* This question is the same as 461: Hamming Distance.

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
class Solution:
    def minBitFlips(self, start: int, goal: int) -> int:
#+end_src

** TODO C++
#+begin_src cpp
class Solution {
public:
    int minBitFlips(int start, int goal) {
        
    }
};
#+end_src