using System;

using System.Linq;

public class Program

{

    public static void Main() {

        var testData = new[] { Tuple.Create(new[] {4, 2, 2, 3, }, 2),

                                Tuple.Create(new[] {4, 2, 0, 3, 1, 2, }, 5),

                                Tuple.Create(new[] {4, 2, 0, }, 0),

                                Tuple.Create(new[] {0, 4, 2, 0, }, 0),

                                Tuple.Create(new[] {0, 4, 2, 0, 3, 1, 2, }, 5),

                                Tuple.Create(new[] {4, 2, 1, 0, 4, 0, 4}, 13),};

​

        foreach (var test in testData) {

            Test(test.Item1, test.Item2);

        }

    }

​

    static void Test(int[] data, int expected) {

        var result = CalculateWaterAmount(data);

​

        Console.WriteLine($"Expected: {expected} Actual: {result}");

        Console.WriteLine(result == expected ? "Passed!" : "Failed!");

    }

​

    static int CalculateWaterAmount(int[] columns) {

        // build matrix

        // analyze matrix

​

        var height = columns.Max();

        var width = columns.Length;

        var matrix = CreateMatrix(width, height);

​

        for (var x = 0; x < width; x++) {

            for (var y = 0; y < columns[x]; y++) {

                matrix[x, y] = 'x';

            }

        }

​

​

        var totalWater = 0;

​

        for (var y = 0; y < height; y++) {

            var countingWater = false;

            var tmpSum = 0;

            for (var x = 0; x < width; x++) {

​

​

                if (matrix[x, y] == 'x') {

                    if (countingWater) {

                        totalWater += tmpSum;

                        tmpSum = 0;

                    }

                    else {

                        countingWater = true;

                    }

                }

                else {

                    if (countingWater) {

                        tmpSum++;

                        matrix[x, y] = 'o';

                    }

                }

​

            }

        }

​

        PrintMatrix(matrix);

​

        return totalWater;

​

    }

​

    static char[,] CreateMatrix(int width, int height) {

        var result = new char[width, height];

        for (var x = 0; x < width; x++) {

            for (var y = 0; y < height; y++) {

                result[x, y] = '-';

​

            }

        }

        return result;

    }

​

    // prints the columns upside down, incorrectly prints water that would overflow

    static void PrintMatrix(char[,] matrix) {

        var width = matrix.GetLength(0);

        var height = matrix.GetLength(1);

​

        for (var y = 0; y < height; y++) {

            for (var x = 0; x < width; x++) {

                Console.Write(matrix[x, y]);

            }

            Console.WriteLine();

        }

    }

​

}