# 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;
}
}
``````

This site uses Akismet to reduce spam. Learn how your comment data is processed.