From 07356b25ed0f8de035dbdef25a5f2118fcac44c2 Mon Sep 17 00:00:00 2001
From: Samat Tolebay <55315928+ordaboy@users.noreply.github.com>
Date: Sun, 4 Oct 2020 00:21:36 +0500
Subject: [PATCH] Create Java - KMPAlgorithm.java

---
 Java - KMPAlgorithm.java | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)
 create mode 100644 Java - KMPAlgorithm.java

diff --git a/Java - KMPAlgorithm.java b/Java - KMPAlgorithm.java
new file mode 100644
index 0000000..4b59011
--- /dev/null
+++ b/Java - KMPAlgorithm.java	
@@ -0,0 +1,34 @@
+public static int[] prefixFunction(String str) {
+    int[] prefixFunc = new int[str.length()];
+    for (int i = 1; i < str.length(); i++) {
+        int j = prefixFunc[i - 1];
+
+        while (j > 0 && str.charAt(i) != str.charAt(j)) {
+            j = prefixFunc[j - 1];
+        }
+        if (str.charAt(i) == str.charAt(j)) {
+            j += 1;
+        }
+        prefixFunc[i] = j;
+    }
+    return prefixFunc;
+}
+
+public static List<Integer> KMPSearch(String text, String pattern) {
+    int[] prefixFunc = prefixFunction(pattern);
+    ArrayList<Integer> occurrences = new ArrayList<Integer>();
+    int j = 0;
+    for (int i = 0; i < text.length(); i++) {
+        while (j > 0 && text.charAt(i) != pattern.charAt(j)) {
+            j = prefixFunc[j - 1];
+        }
+        if (text.charAt(i) == pattern.charAt(j)) {
+            j += 1;
+        }
+        if (j == pattern.length()) {
+            occurrences.add(i - j + 1);
+            j = prefixFunc[j - 1];
+        }
+    }
+    return occurrences;
+}