Second largest element — C# Programming

Problem

Find the second largest number in { 10, 5, 20, 8, 20 } (answer: 10).

Hints

Update first and second when you see a new maximum.

Your practice code

Ready — edit the code above and click Run.

Solution

using System;

class Program
{
    static void Main()
    {
        int[] arr = { 10, 5, 20, 8, 20 };
        int first = int.MinValue, second = int.MinValue;
        foreach (var x in arr)
        {
            if (x > first) { second = first; first = x; }
            else if (x > second && x < first) second = x;
        }
        Console.WriteLine(second);
    }
}

Try solving on your own first, then reveal the official answer.

Explanation

Track two variables in one pass—handles duplicates correctly when second must be strictly less than max.