moddified maps

Author: Alan

Maps/Caching.java

@@ -0,0 +1,50 @@
+import java.util.*;
+public class Caching 
+{
+    static void logLn(Object o){System.out.println(o);}
+    static void log(Object o){System.out.print(o);}
+    /**
+     * naive implementation, takes a long time
+     * @param n
+     * @return fibonaci of the number
+     */
+    static long fib(long n)
+    {
+        if (n==0)
+            return 0;
+        
+        if (n == 1 || n == 2)
+            return 1;
+        
+        return fib(n- 1) + fib(n-2);
+    }
+    /**
+     * optimized implementation using HashMap as cache
+     * @param n
+     * @return fibonaci of the number
+     */
+    static Map<Long, Long> cache = new HashMap<>();
+    static long optFib(long x)
+    {
+        long zero = 0;
+        long one = 1;
+        long two = 2;
+        cache.put(zero,zero);
+        cache.put(one, one);
+        cache.put(two, one);
+
+        if (cache.containsKey(x))
+            return cache.get(x);
+
+        cache.put(x, optFib(x-1)+optFib(x-2));
+        return cache.get(x);
+    }
+
+    public static void main(String [] args)
+    {
+        for (long i =0; i<100; i++)
+        {
+            logLn(i + ": "+ optFib(i));
+        }
+    }
+}

Maps/HashMap.java

@@ -0,0 +1,19 @@
+import java.util.*;
+public class HashMapTest
+{
+       /**
+     * HashMap are not ordered
+     *  
+     * */ 
+    public static void main (String[] args)
+    {
+        Map<String, Integer> m = new HashMap<>();
+        m.put("Timothy",5);
+        m.put("Joey",10);
+        m.put("Dennis",66);
+        m.put("Varshika",-54);
+        m.put("Sanjna",-524);
+        System.out.println(m);
+    }
+
+}

Maps/HashMapTest.java

@@ -0,0 +1,22 @@
+/*
+A linked Hash map maintains the order at which we declare the dictionary values NOT in alphabetical order
+*/
+import java.util.*;
+public class LinkedHashMapTest
+{
+   /**
+     * LinkedHashMap maintain insertion order 
+     *  
+     * */ 
+    public static void main (String[] args)
+    {
+            Map<String, Integer> m = new LinkedHashMap<>();
+            m.put("Timothy",5);
+            m.put("Joey",10);
+            m.put("Dennis",66);
+            m.put("Varshika",-54);
+            m.put("Sanjna",-524);
+            System.out.println(m);
+        
+    }
+}

Maps/LinkedHashMap.java

@@ -1,17 +1,6 @@
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.HashSet;
-import java.util.LinkedHashMap;
-import java.util.LinkedHashSet;
-import java.util.LinkedList;
-import java.util.Map;
-import java.util.Scanner;
-import java.util.Set;
-import java.util.TreeMap;
-import java.util.TreeSet;
+import java.util.*;
 
-public class Main
+public class Sorting
 {
     public static void main (String[] args)
     {

Maps/LinkedHashMapTest.java

@@ -0,0 +1,26 @@
+
+import java.util.*;
+public class TreeMapTest
+{
+    /**
+     * TreeMaps maintain sorted order by keys
+     *  
+     * */ 
+    public static void main (String[] args)
+    {
+	        
+            Map<String, Integer> m = new TreeMap<>();
+            m.put("Timothy",5);
+            m.put("Joey",10);
+            m.put("Dennis",66);
+            m.put("Varshika",-54);
+            m.put("Sanjna",-524);
+            System.out.println(m);
+    }
+}
+/*
+In the console we will have the sorted dictionary in 
+alphabetical order: Dennis(the key)=value of dennis, 
+Joey(the key)=value of Joey, Timothy(the key)=value of Timothy
+*/
+