using System;

public class Program

{

    public static int ReverseInteger(int number)

    {

        int result = 0;

        int reminder;

        int negative = 0;

        if(number < 0)

        {

            number = -number ;

            negative = 1;

        }

        while( number% 10 >= 0 && number >0)

        {

            reminder = number %10;

            result = result * 10 + reminder;

            number = (int)number / 10;

        }

        if(negative == 1)

        {

            result = -result;

        }

        return result;

    }

​

    public static int Question2(int[ ] array)

    {

        int max = array [0]; 

        int second = array[0];

        for(int i=0; i<array.Length; i++)

        {

            if( max < array[i])

            {

                second = max;

                max = array[i];

            }

            else if(array[i]>second && array[i]<max)

            {

                second = array [i];

            }

        }

        return second;

    }

    public static void Question3()

    {

        int[] array = {15,12,17,1};

        for( int i=0 ; i<4; i++)

        {

            int number = 0 + array[i];

            Console.WriteLine( array[i] );

        if ( (number %2 == 0) || (number %3 ==0) || (number% 5== 0))

            {

                Console.WriteLine("true");

            }

        else 

            {

                Console.WriteLine("false");

            }

        }   

    }

    public static int Question4(int[ ] array)

    {

        int n = array.Length;

        int allsum = (n+0)*(n+1)/2; //在沒有遺漏數字下的總和

        int sum = 0; //有遺漏數字下的總和

        int missing = 0;

        for(int i=0; i<array.Length ; i++)

        {

            sum = sum + array[i] ;

            missing = allsum - sum ;

        }

        return missing;

    }

    public static int Question5(int[ ] array)

    {       

        int n = array.Length; 

        int count = 0; //計數器

        int currentcount = 1; //即時計數器

        for (int i=0; i<n; i++) 

        { 

            if (i < n-1 && array[i] == array[i+1]) //前一個束子和現在數字相同

            {

                currentcount ++; //即時計數器加一

            }

            else

            { 

                if (currentcount > count) //即時計數器是否是最大的

                { 

                    count = currentcount; 

                } 

                currentcount = 1; 

            } 

         }

        return count; 

    }

​

     public static void Main()

    {

        // Question1

        Console.WriteLine("123 to " + ReverseInteger(123));

        Console.WriteLine("-123 to " + ReverseInteger(-123)); 

        //Question2

        int[ ] array1 = {1,2,3,4,5,6,7};

        int[ ] array2 = {9,3,6,12,5,7};

        Console.WriteLine(Question2(array1) );

        Console.WriteLine(Question2(array2) ); 

        Question3();

        //Question4

        int[ ] array3 = {1,3,2,5,0};

        int[ ] array4 = {8,6,4,1,3,2,5,0 };

        Console.WriteLine(Question4(array3) );

        Console.WriteLine(Question4(array4) ); 

        //Question5

        int[ ] array5 = {1,1,1,1,0,0,1,1,1};

        int[ ] array6 = {1,1,0,0,1,1,1,1,1,1};

        Console.WriteLine(Question5(array5) );

        Console.WriteLine(Question5(array6) ); 

     }

}