Add LongestCommonPrefix (#5849)

src/main/java/com/thealgorithms/strings/LongestCommonPrefix.java

@@ -0,0 +1,22 @@
+package com.thealgorithms.strings;
+
+import java.util.Arrays;
+
+public final class LongestCommonPrefix {
+    public String longestCommonPrefix(String[] strs) {
+        if (strs == null || strs.length == 0) {
+            return "";
+        }
+
+        Arrays.sort(strs);
+        String shortest = strs[0];
+        String longest = strs[strs.length - 1];
+
+        int index = 0;
+        while (index < shortest.length() && index < longest.length() && shortest.charAt(index) == longest.charAt(index)) {
+            index++;
+        }
+
+        return shortest.substring(0, index);
+    }
+}