Arrays.js

'use strict';

process.stdin.resume();
process.stdin.setEncoding('utf-8');

let inputString = '';
let currentLine = 0;

process.stdin.on('data', inputStdin => {
    inputString += inputStdin;
});

process.stdin.on('end', _ => {
    inputString = inputString.trim().split('\n').map(string => {
        return string.trim();
    });
    
    main();    
});

function readLine() {
    return inputString[currentLine++];
}
/**
*   Return the second largest number in the array.
*   @param {Number[]} nums - An array of numbers.
*   @return {Number} The second largest number in the array.
**/
function getSecondLargest(nums) {
    // Complete the function
    var sorted_array = nums.sort(function (a, b) { return a - b; });
    var unique_sorted_array = sorted_array.filter(function (elem, index, self) {
        return index === self.indexOf(elem);
    })

    return unique_sorted_array[unique_sorted_array.length - 2];
}

function main() {
    const n = +(readLine());
    const nums = readLine().split(' ').map(Number);
    
    console.log(getSecondLargest(nums));
}