C# programming exercises - examples with solutions

Three increasing adjacent

Given an array of numbers, write a method that checks if there are three adjacent numbers where second is greater by 1 than the first one and third is greater by 1 than the second one.

Expected input and output

ThreeIncreasingAdjacent([45, 23, 44, 68, 65, 70, 80, 81, 82 ]) → True ThreeIncreasingAdjacent([7, 3, 5, 8, 9, 3, 1, 4 ]) → False

Click here to see example solution

using System;

namespace CSharpExercises.Exercises.Loops
{
    class ThreeIncreasingAdjacentTask
    {
        static bool ThreeIncreasingAdjacent(int[] arr)
        {
            bool found = false;
            for (int i = 1; i <= arr.Length - 2; i++)
            {
                if (arr[i - 1] + 1 == arr[i] && arr[i + 1] - 1 == arr[i])
                {
                    found = true;
                }
            }

            return found;
        }

        static void Main(string[] args)
        {
            Console.WriteLine(ThreeIncreasingAdjacent(new int[] { 7, 8, 9, 2, 4, 5, 0 }));                // True
            Console.WriteLine(ThreeIncreasingAdjacent(new int[] { -9, 0, -1, -6, -5, -4, -8, 0 }));       // True
            Console.WriteLine(ThreeIncreasingAdjacent(new int[] { 15, 17, 14, 11, 18, 19, 16, 16 }));     // False
        }
    }
}