package main

import (
    "math"
)

func reverse(x int) int {
    var res int32

    var mul int32 = 1
    if x < 0 {
        mul = -1
        x *= -1
    }

    for x != 0 {
        digit := mul * int32(x % 10)
        if mul > 0 && (math.MaxInt32 - digit) / 10 < res {
            return 0
        }
        if mul < 0 && (math.MinInt32 - digit) / 10 > res {
            return 0
        }

        res = res * 10 + digit
        x /= 10
    }

    return int(res)
}