From 81d1a97304b9911d7c4ddfef0f3e2776ff5134de Mon Sep 17 00:00:00 2001
From: Chris Cameron <chris.cameron@icdsystems.com>
Date: Tue, 1 Dec 2020 16:53:10 -0500
Subject: [PATCH] feat: Added DepthFirstSearch method to RecursionUtils

---
 ICD.Common.Utils/RecursionUtils.cs | 34 ++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/ICD.Common.Utils/RecursionUtils.cs b/ICD.Common.Utils/RecursionUtils.cs
index f6a427a..a0bca92 100644
--- a/ICD.Common.Utils/RecursionUtils.cs
+++ b/ICD.Common.Utils/RecursionUtils.cs
@@ -462,5 +462,39 @@ namespace ICD.Common.Utils
 				start = next;
 			}
 		}
+
+		/// <summary>
+		/// Returns all of the nodes in the tree via depth-first search.
+		/// </summary>
+		/// <typeparam name="T"></typeparam>
+		/// <param name="root"></param>
+		/// <param name="getChildren"></param>
+		/// <returns></returns>
+		[NotNull]
+		public static IEnumerable<T> DepthFirstSearch<T>([NotNull] T root, [NotNull] Func<T, IEnumerable<T>> getChildren)
+		{
+			if (root == null)
+				throw new ArgumentNullException("root");
+
+			if (getChildren == null)
+				throw new ArgumentNullException("getChildren");
+
+			IcdHashSet<T> visited = new IcdHashSet<T>();
+			Stack<T> stack = new Stack<T>();
+
+			stack.Push(root);
+
+			while (stack.Count != 0)
+			{
+				T current = stack.Pop();
+				if (!visited.Add(current))
+					continue;
+
+				yield return current;
+
+				foreach (T child in getChildren(current).Reverse())
+					stack.Push(child);
+			}
+		}
 	}
 }