From 0ad4284cbd0521138f22934cb6e5392dff04495e Mon Sep 17 00:00:00 2001
From: unknown <shuyinliu2011@gmail.com>
Date: Wed, 29 Oct 2025 21:13:27 -0700
Subject: [PATCH] Add an implementation of finding the longest common prefix of
 an array of strings. Print out empty string if there is no common prefix. I
 aim this to be counted towards the Hacktoberfest.

---
 Java/LargestCommonPrefix.java | 41 +++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 Java/LargestCommonPrefix.java

diff --git a/Java/LargestCommonPrefix.java b/Java/LargestCommonPrefix.java
new file mode 100644
index 0000000..6867a1d
--- /dev/null
+++ b/Java/LargestCommonPrefix.java
@@ -0,0 +1,41 @@
+/* Author : Shuyin Liu
+ * Problem : To find the longest common prefix string amongst an array of strings, input on command line.
+ * Explanation : Sample command --  java LongestCommonPrefix apple application appointment
+ */
+class LongestCommonPrefix {
+    public static void main(String[] args) {
+        System.out.print("The common prefix is:");
+        if (args.length == 0) {
+            System.out.println("");
+            return;
+        }
+        if (args.length == 1) {
+            System.out.println(args[0]);
+            return;
+        }
+
+        String prev = args[0];
+
+        for (int i = 1; i < args.length; i++) {
+            prev = getCommonPrefix(prev, args[i]);
+            if (prev.isEmpty()) {
+                System.out.println("");
+                return;
+            }
+        }
+
+        System.out.println(prev);
+    }
+
+    private static String getCommonPrefix(String a, String b) {
+        StringBuilder sb = new StringBuilder();
+        for (int i = 0; i < a.length() && i < b.length(); i++) {
+            if (a.charAt(i) == b.charAt(i)) {
+                sb.append(a.charAt(i));
+            } else {
+                break;
+            }
+        }
+        return sb.toString();
+    }
+}
\ No newline at end of file