Solution: Collect Coins in Minimum Steps

using System;
public class Program
{
    /// <summary>
    /// Helper recursive method to calculate the minimum steps required to collect coins from a array.
    /// </summary>
    /// <param name="arr">Array of coin stacks.</param>
    /// <param name="left">Left index of the array.</param>
    /// <param name="right">Right index of the array.</param>
    /// <param name="h">Height of the stack.</param>
    /// <returns>The minimum number of steps to collect coins from the array. Returns 0 if no steps are required.</returns>
    public static int MinimumStepsRecursive(int[] arr, int left, int right, int h)
    {
        // Base Case: When left is greater or equal to right
        if (left >= right)
        {
            return 0;
        }
        // Find the index with the minimum height in the current segment
        int minimumHeight = left;
        for (int i = left; i < right; i++)
        {
            if (arr[i] < arr[minimumHeight])
            {
                minimumHeight = i;
            }
        }
        // Collecting all vertical line coins and horizontal line coins on both sides
        return Math.Min(right - left,
            MinimumStepsRecursive(arr, left, minimumHeight, arr[minimumHeight]) +
            MinimumStepsRecursive(arr, minimumHeight + 1, right, arr[minimumHeight]) +
            arr[minimumHeight] - h);
    }
    /// <summary>
    /// Method which calculates the minimum steps to collect coins from the array
    /// </summary>
    /// <param name="arr">Array of coin stacks.</param>
    /// <returns>The minimum number of steps to collect coins from the array. Returns 0 if no steps are required.</returns>
    public static int MinimumSteps(int[] arr)
    {
        return MinimumStepsRecursive(arr, 0, arr.Length, 0);
    }
    // Driver code to test the above method
    public static void Main(string[] args)
    {
        int[] arr = { 2, 1, 2, 5, 1 };
        Console.WriteLine("Minimum number of steps: " + MinimumSteps(arr));
    }
}