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. 1 <= X <= 10^9
2. 1 <= Y <= 10^9

# @lc code=start
using LeetCode

function broken_calc(x::Integer, y::Integer)
    cnt = 0
    while x < y
        isodd(y) ? (y += 1) : y >>= 1
        cnt += 1
    end
    return cnt + x - y
end
# @lc code=end

broken_calc (generic function with 1 method)

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