991. Broken Calculator

There is a broken calculator that has the integer startValue on its display initially. In one operation, you can:

• multiply the number on display by 2, or
• subtract 1 from the number on display.

Given two integers startValue and target, return the minimum number of operations needed to display target on the calculator.

class Solution {
public:
    int brokenCalc(int X, int Y) {
        int res = 0;
        while(Y > X) {
            if(Y&1) Y += 1;
            else Y>>=1;
            res++;
        }
        return res + X - Y;
    }
};