991. Broken Calculator

On a broken calculator that has a number showing on its display, we can perform two operations:

Double: Multiply the number on the display by 2, or;
Decrement: Subtract 1 from the number on the display.
Initially, the calculator is displaying the number X.

Return the minimum number of operations needed to display the number Y.

Example 1:

Input: X = 2, Y = 3
Output: 2
Explanation: Use double operation and then decrement operation {2 -> 4 -> 3}.

Example 2:

Input: X = 5, Y = 8
Output: 2

Explanation: Use decrement and then double {5 -> 4 -> 8}.

Example 3:

Input: X = 3, Y = 10
Output: 3

Explanation: Use double, decrement and double {3 -> 6 -> 5 -> 10}.

Example 4:

Input: X = 1024, Y = 1
Output: 1023

Explanation: Use decrement operations 1023 times.

Note:

1 <= X <= 109
1 <= Y <= 109

class Solution {

    /**
     * @param Integer $x
     * @param Integer $y
     * @return Integer
     */
    function brokenCalc($x, $y) {
        $c = 0;
        while($x < $y){
           if($y % 2 == 0){
                $y /= 2;
            } else {
                $y ++;
           } 
            $c ++;
        }
        return $c + $x - $y;
    }
}

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