You are given two positive integers low and high. An integer x consisting of 2 * n digits is symmetric if the sum of the first n digits of x is equal to the sum of the last n digits of x. Numbers with an odd number of digits are never symmetric. Re

countSymmetricIntegers.js

/**
 * @param {number} low
 * @param {number} high
 * @return {number}
 */
// Function to check if a number has an even number of digits
function hasEvenDigits(num) {
    const digitCount = num.toString().length;
    return digitCount % 2 === 0; // True if the digit count is even
}

// Function to split a number into two halves and check if they are symmetric
function isSymmetric(num) {
    const numStr = num.toString();
    const n = numStr.length / 2; // Half the number of digits
    const firstHalf = numStr.slice(0, n); // First n digits
    const secondHalf = numStr.slice(n); // Last n digits

    // Calculate the sum of each half
    const sumFirstHalf = firstHalf.split('').reduce((acc, digit) => acc + parseInt(digit), 0);
    const sumSecondHalf = secondHalf.split('').reduce((acc, digit) => acc + parseInt(digit), 0);

    return sumFirstHalf === sumSecondHalf; // Check if both sums are equal
}

// Main function to count symmetric integers in the range [low, high]
var countSymmetricIntegers = function(low, high) {
    let count = 0; // Intialize counter

    for (let num = low; num <= high; num++) {
        if (hasEvenDigits(num) && isSymmetric(num)) {
            count++; // Increment count if the number is symmetric
        }
    }

    return count; // return the total count
};