From f4596155b290d822075290acd2015a182a845c6e Mon Sep 17 00:00:00 2001
From: Jason Staten <code@jxs.me>
Date: Wed, 28 Sep 2022 00:50:16 -0600
Subject: [PATCH] longestprefix

---
 longestprefix/longestprefix.go      | 28 ++++++++++++++++
 longestprefix/longestprefix_test.go | 52 +++++++++++++++++++++++++++++
 longestprefix/readme.md             | 25 ++++++++++++++
 3 files changed, 105 insertions(+)
 create mode 100644 longestprefix/longestprefix.go
 create mode 100644 longestprefix/longestprefix_test.go
 create mode 100644 longestprefix/readme.md

diff --git a/longestprefix/longestprefix.go b/longestprefix/longestprefix.go
new file mode 100644
index 0000000..011f11b
--- /dev/null
+++ b/longestprefix/longestprefix.go
@@ -0,0 +1,28 @@
+package longestprefix
+
+import (
+	"strings"
+)
+
+func LongestCommonPrefix(strs []string) string {
+	result := ""
+
+	if len(strs) == 0 {
+		return result
+	}
+
+	first := strs[0]
+	rest := strs[1:]
+
+	for i := range first {
+		prefix := first[:i+1]
+		for _, s := range rest {
+			if !strings.HasPrefix(s, prefix) {
+				return result
+			}
+		}
+		result = prefix
+	}
+
+	return first
+}
diff --git a/longestprefix/longestprefix_test.go b/longestprefix/longestprefix_test.go
new file mode 100644
index 0000000..da6301f
--- /dev/null
+++ b/longestprefix/longestprefix_test.go
@@ -0,0 +1,52 @@
+package longestprefix_test
+
+import (
+	"testing"
+
+	"git.jxs.me/leetgo/longestprefix"
+)
+
+func TestEmpty(t *testing.T) {
+	expected := ""
+	result := longestprefix.LongestCommonPrefix([]string{})
+
+	if expected != result {
+		t.Errorf("%q != %q", expected, result)
+	}
+}
+
+func TestSingle(t *testing.T) {
+	expected := "bark"
+	result := longestprefix.LongestCommonPrefix([]string{
+		"bark",
+	})
+
+	if expected != result {
+		t.Errorf("%q != %q", expected, result)
+	}
+}
+
+func TestSimple(t *testing.T) {
+	expected := "ye"
+	result := longestprefix.LongestCommonPrefix([]string{
+		"yes",
+		"yeet",
+	})
+
+	if expected != result {
+		t.Errorf("%q != %q", expected, result)
+	}
+}
+
+func TestExample(t *testing.T) {
+	expected := "fl"
+	result := longestprefix.LongestCommonPrefix([]string{
+		"flower",
+		"flow",
+		"flight",
+	})
+
+	if expected != result {
+		t.Errorf("%q != %q", expected, result)
+	}
+}
diff --git a/longestprefix/readme.md b/longestprefix/readme.md
new file mode 100644
index 0000000..af683fa
--- /dev/null
+++ b/longestprefix/readme.md
@@ -0,0 +1,25 @@
+Write a function to find the longest common prefix string amongst an array of strings.
+
+If there is no common prefix, return an empty string "".
+
+ 
+
+Example 1:
+
+Input: strs = ["flower","flow","flight"]
+Output: "fl"
+
+Example 2:
+
+Input: strs = ["dog","racecar","car"]
+Output: ""
+Explanation: There is no common prefix among the input strings.
+
+ 
+
+Constraints:
+
+    1 <= strs.length <= 200
+    0 <= strs[i].length <= 200
+    strs[i] consists of only lowercase English letters.
+