using System; using System.Collections.Generic; using System.Linq; class MainClass { static void Main() { int[] nums = {2, 7, 9, 3, 1}; int maxValue = 0; int prevValue = 0; int prevPrevValue = 0; for(var i=0; i < nums.Length; i++){ maxValue = Math.Max(prevValue, prevPrevValue + nums[i]); prevPrevValue = prevValue; prevValue = maxValue; } Console.WriteLine(maxValue); } }