Created
September 26, 2015 00:36
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using System; | |
using System.Collections.Generic; | |
using System.Linq; | |
using NUnit.Framework; | |
using NUnitLite.Runner; | |
namespace PoisonousPlants | |
{ | |
public class Program | |
{ | |
public static void Main(string[] args) | |
{ | |
new TextUI().Execute(new[] { "-noheader" }); | |
} | |
private static int Solve(IEnumerable<int> pesticides) | |
{ | |
var plants = new Stack<Plant>(); | |
var maxDaysAlive = 0; | |
foreach (var pesticide in pesticides) | |
{ | |
var daysAlive = 0; | |
while (plants.Count > 0 && pesticide <= plants.Peek().Pesticide) | |
{ | |
daysAlive = Math.Max(daysAlive, plants.Pop().DaysAlive); | |
} | |
daysAlive = plants.Count == 0 ? 0 : daysAlive + 1; | |
maxDaysAlive = Math.Max(maxDaysAlive, daysAlive); | |
plants.Push(new Plant(pesticide, daysAlive)); | |
} | |
return maxDaysAlive; | |
} | |
private struct Plant | |
{ | |
public Plant(int pesticide, int daysAlive) | |
{ | |
Pesticide = pesticide; | |
DaysAlive = daysAlive; | |
} | |
public int Pesticide { get; } | |
public int DaysAlive { get; } | |
} | |
[Test] | |
public void SolutionWorksForSampleInput() | |
{ | |
var input = new[] {6, 5, 8, 4, 7, 10, 9}; | |
Assert.AreEqual(2, Solve(input)); | |
} | |
[Test] | |
public void SolutionSolvesPathologicalCaseQuickly() | |
{ | |
const int inputSize = 100000; | |
var input = new[] {1}.Concat(Enumerable.Repeat(2, inputSize - 1)); | |
Assert.AreEqual(inputSize - 1, Solve(input)); | |
} | |
} | |
} |
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