using System;
using System.IO;
using System.Linq;

namespace Wunderpahkina_vol6
{
    class Program
    {
        static void Main(string[] args)
        {
            var lines = File.ReadAllLines("input.txt");
            var solver = new Solver(lines.Select(int.Parse).ToArray());
            var result = solver.Solve();
            Console.WriteLine($"Biggest square: {result} units x {result} units (Area: {result * result} units^2)");
        }
    }

    public class Solver
    {
        private readonly int[] _data;

        public Solver(int[] data)
        {
            _data = data;
        }

        public int Solve()
        {
            int rangeMin = 0;
            int rangeMax = _data.Length;
            while (rangeMin + 1 < rangeMax)
            {
                // go through the sizes of squares by dividing and conquering
                int pivot = rangeMin + (rangeMax - rangeMin) / 2;
                // can a square with with a side size like the "pivot" fit?
                var canFit = CanFit(pivot);
                Console.WriteLine($"Does a square with a side of {pivot} fit? {canFit}");

                if (canFit)
                {
                    rangeMin = pivot;
                }
                else
                {
                    rangeMax = pivot;
                }
            }

            return rangeMin;
        }

        private bool CanFit(int side)
        {
            var consecutiveTallEnoughColumns = 0;
            for (int index = 0; index < _data.Length; index++)
            {
                if (_data[index] >= side)
                {
                    consecutiveTallEnoughColumns++;
                    if (consecutiveTallEnoughColumns == side) return true;
                }
                else
                {
                    consecutiveTallEnoughColumns = 0;
                }
            }
            return false;
        }
    }
}