z function added

Strings/ZFunction.java

@@ -0,0 +1,29 @@
+package Strings;
+
+public class ZFunction {
+    private String s;
+
+    public ZFunction(String s){
+        this.s = s;
+    }
+
+    public int[] getArray(){
+        int length = s.length();
+        int[] z = new int[length];
+        int l = 0, r = 0;
+        for (int i=0; i<length; i++){
+            if (i > l && i <= r){
+                z[i] = Math.min(z[i - l], r - i + 1);
+            }
+            while (i + z[i] < length && s.charAt(z[i]) == s.charAt(i + z[i])){
+                z[i]++;
+            }
+            if (i + z[i] > r){
+                l = i;
+                r = i + z[i] - 1;
+            }
+        }
+
+        return z;
+    }
+}