add introduction header

lhmzhou · web-flow · commit a5ec6d8bc087 · 2022-10-14T20:53:04.000-05:00
diff --git a/strings_arrays/binary_search.md b/strings_arrays/binary_search.md
@@ -1,3 +1,5 @@
+### Introduction
+
 Binary search is a technique for efficiently locating an element in a sorted list. Searching for an element can done naively in **O(n)** time by checking every element in the list, but binary search's optimization speeds it up to **O(log n)**. Binary search is a great tool to keep in mind for array problems.
 
 Algorithm

Original file line number	Diff line number	Diff line change
`@@ -1,3 +1,5 @@`
	`1`	`+### Introduction`
	`2`	`+`
`1`	`3`	`Binary search is a technique for efficiently locating an element in a sorted list. Searching for an element can done naively in O(n) time by checking every element in the list, but binary search's optimization speeds it up to O(log n). Binary search is a great tool to keep in mind for array problems.`
`2`	`4`
`3`	`5`	`Algorithm`