Fix reference to wrong traversal algorithm

Fixes #105

algorithms/README.md

@@ -490,7 +490,7 @@ Recursion is a common approach for trees. When you notice that the subtree probl
 
 When using recursion, always remember to check for the base case, usually where the node is `null`.
 
-When you are asked to traverse a tree by level, use depth first search.
+When you are asked to traverse a tree by level, use breadth-first search.
 
 Sometimes it is possible that your recursive function needs to return two values.