PageFlowSplitter

PageFlowSplitter

using System;
using System.Collections.Generic;
using Microsoft.VisualStudio.TestTools.UnitTesting;
using System.Linq;

namespace PageflowBreaker
{
    [TestClass]
    public class UnitTest1
    {
        // Sample real output:       a  a  b  b  c  c  c  d  d  d  d
        // Expected after managed:   a  a |  b  b |  c  c  c |  d  d  d |  d
        // Incorrect after managed:  a  a  b  b |  c  c  c | d  d  d  d
        
        [TestMethod]
        public void NoFlow()
        {
            List<string> pageBreaks = new List<string> 
                { "a", "a", "b", "b", "c", "c", "c", "d", "d", "d", "d" };

            IEnumerable<ItemRow> breakPositions = AnalyzePageflow(pageBreaks);
            
            // Tests
            CollectionAssert
                .AreEqual(new List<int> { 1, 3, 6, 9, 10 }, 
                breakPositions.Select(d => d.Pos).ToList());

            CollectionAssert
                .AreEqual(new List<int> { 3, 6, 8 }, 
                breakPositions.Select(d => d.Pos).ToList());
            // End tests
        }

        protected IEnumerable<ItemRow> AnalyzePageflow(IEnumerable<string> pageBreaks)
        {
           int magicNumber = 3;
            var splitted = (from p in pageBreaks
                            group p by new { Breaker = p } into gr
                            select new ItemRow {
                               Letter = gr.Key.Breaker,
                               Qty = gr.Count()
                           }).ToList();

            foreach (var item in splitted.Where(d => d.Qty > magicNumber).ToArray())
            {
                int remainder = magicNumber;
                while (item.Qty > 0)
                {
                    if (item.Qty < remainder)
                        remainder = item.Qty % magicNumber;

                    splitted.Add(new ItemRow() { Qty = remainder, Letter = item.Letter });
                    item.Qty -= remainder;
                }
                splitted.Remove(item);
            }

            int position = -1; // Position start index with base = 0 due to requirement
            foreach (var item in splitted)
            {
                position += item.Qty;
                item.Pos += position;
            }
            return splitted;
        }

        public class ItemRow
        {
            public string Letter { get; set; }
            public int Qty { get; set; }
            public int Pos { get; set; }
        }
    }
}