JavaScript: Maximum value swapping two digits in an integer

JavaScript Math: Exercise-112 with Solution

Write a JavaScript program to calculate the maximum value by swapping two digits in a given integer.

Test Data:
(100) -> 100
(120) -> 210
(129) -> 921

Sample Solution:

JavaScript Code:

/**
 * Function to find the maximum value by swapping two digits in the given integer.
 * @param {number} n - The integer.
 * @returns {number} - The maximum value obtained after swapping two digits, if any.
 */
function test(n) {
    // Convert the integer to a string
    var n_str = n.toString();
    
    // Loop through each digit of the integer
    for (var i = 0; i < n_str.length; i++) {
        var t = n_str[i]; // Current digit
        var index = i; // Index of the current digit
            
        // Find the maximum digit greater than the current digit
        for (var x = n_str.length - 1; x > i; x--) {
            if (n_str[x] > t) {
                t = n_str[x];
                index = x;
            }
        }
        
        // If a greater digit is found, swap the digits and return the new integer
        if (t != n_str[i]) {
            var nums = n_str.split('');
            
            var tmp = nums[i];
            
            nums[i] = nums[index];
            nums[index] = tmp;
            
            return parseInt(nums.join(''));
        }
    }
    // If no swap is possible, return the original integer
    return n;
}

// Test cases
n = 100;
console.log("n = " + n);
console.log("Maximum value swapping two digits in the said integer: " + test(n));
n = 120;
console.log("n = " + n);
console.log("Maximum value swapping two digits in the said integer: " + test(n));
n = 129;
console.log("Maximum value swapping two digits in the said integer: " + test(n));
console.log("e: " + test(n));

Output:

n = 100
Maximum value swapping two digits in the said integer: 100
n = 120
Maximum value swapping two digits in the said integer: 210
Maximum value swapping two digits in the said integer: 921
e: 921

Flowchart:

Live Demo:

See the Pen javascript-math-exercise-112 by w3resource (@w3resource) on CodePen.

Improve this sample solution and post your code through Disqus.

Previous: Kth smallest number in a multiplication table.
Next: Smallest number whose digits multiply to a number.