Reverse Integer

Reverse Integer - LeetCodeLeetCode

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

Constraints:

• -231 <= x <= 231 - 1

You can solve this problem by converting the integer to a string, reversing the string, handling the sign, and converting it back to an integer. Here's a JavaScript implementation:

function reverse(x) {
    const sign = Math.sign(x);
    const reversed = parseInt(Math.abs(x).toString().split('').reverse().join('')) * sign;
    
    if (reversed < Math.pow(-2, 31) || reversed > Math.pow(2, 31) - 1) {
        return 0;
    }
    
    return reversed;
}

// Test cases
console.log(reverse(123));   // Output: 321
console.log(reverse(-123));  // Output: -321
console.log(reverse(120));   // Output: 21

This reverse function takes an integer x. It first determines the sign of x using Math.sign. Then, it converts the absolute value of x to a string, reverses it, and converts it back to an integer. Finally, it checks if the reversed integer falls within the 32-bit signed integer range and returns the result accordingly.