implemented Z algorithm for pattern matching :)

Author: jumbuna

src/com/jumbuna/algs/Zalgorithm.java

@@ -0,0 +1,49 @@
+package com.jumbuna.algs;
+
+import com.jumbuna.ds.Vector;
+
+public class Zalgorithm {
+	public static Vector<Integer> subStringSearch(String text, String pattern, char separator) {
+		String concated = pattern + separator + text;
+		Vector<Integer> zArray = new Vector<>();
+		Vector<Integer> vec = new Vector<>();
+		//(m+n) time Z-array construction
+		zArray.insert(0);
+		int i = 0;
+		for(int j = 1; j < concated.length(); j++) {
+			int startIndex = j + i;
+			while(concated.charAt(startIndex) == concated.charAt(i) && startIndex < concated.length()) {
+				++i;
+				++startIndex;
+			}
+			zArray.insert(i);
+			if(i == pattern.length()) {
+				vec.insert(zArray.size()-2-pattern.length());
+			}
+			if(i <= 1) {
+				i = 0;
+			}else {
+				int k = 1;
+				for(; (zArray.elementAt(k) + j + k) < startIndex && k < i; k++) {
+					zArray.insert(zArray.elementAt(k));
+					++j;
+				}
+				if(k == i) {
+					i = 0;
+					--j;
+				}else {
+					i = zArray.elementAt(k);
+				}
+			}
+		}
+		
+		return vec;
+	}
+	
+	public static void main(String[] args) {
+		Vector<Integer> vec = Zalgorithm.subStringSearch("abacaccdaabaabad", "aba", '&');
+		for(int i = 0; i < vec.size(); i++) {
+			System.out.println(vec.elementAt(i));
+		}
+	}
+}