2220. Minimum Bit Flips to Convert Number

problem

solution

class Solution {
public:
    int minBitFlips(int start, int goal) {
        int n = start^goal, count = 0;
        // count one
        while(n){
            n &=(n-1);
            count++;
        }
        return count;
        
    }
};

analysis

• time complexity O(n)
• space complexity O(1)