7. Reverse Integer | LeetCode | Interview Question | Java

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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

class Solution {
    public int reverse(int x) {
        int rev = 0;
        while (x != 0) {
            int pop = x % 10;
            x /= 10;

            if (rev > Integer.MAX_VALUE/10 || 
                (rev == Integer.MAX_VALUE / 10 && pop > 7)) 
                return 0;

            if (rev < Integer.MIN_VALUE/10 || 
                (rev == Integer.MIN_VALUE / 10 && pop < -8)) 
                    return 0;

            rev = rev * 10 + pop;
        }
        return rev;
    }
}

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