SherlockAndCost.cs

// https://www.hackerrank.com/challenges/sherlock-and-cost/problem
using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;

class Solution
{

    // Complete the cost function below.
    static int cost(int[] B)
    {
        var ifOnePicked = 0;
        var ifValuePicked = 0;
        for (var index = 1; index < B.Length; index++)
        {
            var fromOneToValue = B[index] - 1;
            var fromValueToOne = B[index - 1] - 1;
            var fromPreviousValueToValue = Math.Abs(B[index] - B[index - 1]);

            var nextIfOnePicked = Math.Max(ifOnePicked, ifValuePicked + fromValueToOne);
            var nextIfValuePicked = Math.Max(ifValuePicked + fromPreviousValueToValue, ifOnePicked + fromOneToValue);

            ifOnePicked = nextIfOnePicked;
            ifValuePicked = nextIfValuePicked;
        }

        return Math.Max(ifOnePicked, ifValuePicked);
    }

    static void Main(string[] args)
    {
        TextWriter textWriter = new StreamWriter(@System.Environment.GetEnvironmentVariable("OUTPUT_PATH"), true);

        int t = Convert.ToInt32(Console.ReadLine());

        for (int tItr = 0; tItr < t; tItr++)
        {
            int n = Convert.ToInt32(Console.ReadLine());

            int[] B = Array.ConvertAll(Console.ReadLine().Split(' '), BTemp => Convert.ToInt32(BTemp))
            ;
            int result = cost(B);

            textWriter.WriteLine(result);
        }

        textWriter.Flush();
        textWriter.Close();
    }
}