LeetCode-in-All
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
import "math"
func reverse(x int) int {
var r int
for ok := true; ok; ok = x != 0 {
if r > math.MaxInt32/10 || r < math.MinInt32/10 {
return 0
}
r = (x % 10) + (r * 10)
x /= 10
}
return r
}