From 2a295545a79b89c18447e0aee599eb5a6c27a04e Mon Sep 17 00:00:00 2001
From: HoLLy <dario.db@hotmail.com>
Date: Wed, 29 May 2019 11:25:25 +0200
Subject: [PATCH] Don't mutate strainPeaks

---
 osu.Game/Rulesets/Difficulty/Skills/Skill.cs | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/osu.Game/Rulesets/Difficulty/Skills/Skill.cs b/osu.Game/Rulesets/Difficulty/Skills/Skill.cs
index e8020ed185..227f2f4018 100644
--- a/osu.Game/Rulesets/Difficulty/Skills/Skill.cs
+++ b/osu.Game/Rulesets/Difficulty/Skills/Skill.cs
@@ -3,6 +3,7 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using osu.Game.Rulesets.Difficulty.Preprocessing;
 using osu.Game.Rulesets.Difficulty.Utils;
 
@@ -17,7 +18,7 @@ namespace osu.Game.Rulesets.Difficulty.Skills
         /// <summary>
         /// The peak strain for each <see cref="DifficultyCalculator.SectionLength"/> section of the beatmap.
         /// </summary>
-        public IList<double> StrainPeaks => strainPeaks;
+        public IReadOnlyList<double> StrainPeaks => strainPeaks;
 
         /// <summary>
         /// Strain values are multiplied by this number for the given skill. Used to balance the value of different skills between each other.
@@ -84,13 +85,12 @@ namespace osu.Game.Rulesets.Difficulty.Skills
         /// </summary>
         public double DifficultyValue()
         {
-            strainPeaks.Sort((a, b) => b.CompareTo(a)); // Sort from highest to lowest strain.
-
             double difficulty = 0;
             double weight = 1;
 
             // Difficulty is the weighted sum of the highest strains from every section.
-            foreach (double strain in strainPeaks)
+            // We're sorting from highest to lowest strain.
+            foreach (double strain in strainPeaks.OrderByDescending(d => d))
             {
                 difficulty += strain * weight;
                 weight *= DecayWeight;