LeetCode in Kotlin

7. Reverse Integer

Medium

Given a signed 32-bit integer x, return x with its digits reversed. If reversing x causes the value to go outside the signed 32-bit integer range [-231, 231 - 1], then return 0.

Assume the environment does not allow you to store 64-bit integers (signed or unsigned).

Example 1:

Input: x = 123

Output: 321

Example 2:

Input: x = -123

Output: -321

Example 3:

Input: x = 120

Output: 21

Example 4:

Input: x = 0

Output: 0

Constraints:

• -231 <= x <= 231 - 1

Solution

class Solution {
    fun reverse(x: Int): Int {
        var rev: Long = 0
        var localX = x
        while (localX != 0) {
            rev = (rev * 10) + (localX % 10)
            localX /= 10
        }
        if (rev > Integer.MAX_VALUE || rev < Integer.MIN_VALUE) {
            return 0
        }
        return rev.toInt()
    }
}

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