Happy Number

Java/AbundantNumber.java

@@ -0,0 +1,36 @@
+import static java.util.stream.LongStream.rangeClosed;
+public class Exercise2 {
+
+   public static void main(String[] args) {
+        int count_Deficient_no = 0;
+        int count_Perfect_no = 0;
+        int count_Abundant_no = 0;
+
+        for (long i = 1; i <= 10_000L; i++) {
+            long sum = proper_Divs_Sum(i);
+            if (sum < i)
+                count_Deficient_no++;
+            else if (sum == i)
+                count_Perfect_no++;
+            else
+                count_Abundant_no++;
+        }
+        System.out.println("Number Counting [(integers) between 1 to 10,000]: ");
+        System.out.println("Deficient number: " + count_Deficient_no);
+        System.out.println("Perfect number: " + count_Perfect_no);
+        System.out.println("Abundant number: " + count_Abundant_no);
+    }
+     public static Long proper_Divs_Sum(long num) {
+        return rangeClosed(1, (num + 1) / 2).filter(i -> num % i == 0 && num != i).sum();
+    }
+}
+
+/*
+Time complexity : O(n)
+Space complexity : O(n)
+
+Number Counting [(integers) between 1 to 10,000]:                                                             
+Deficient number: 7508                                                                                        
+Perfect number: 4                                                                                             
+Abundant number: 2488
+*/

Java/EvilNumber.java

@@ -0,0 +1,64 @@
+import java.util.*;
+class EvilNumber
+{
+    String toBinary(int n) // Function to convert a number to Binary
+    {
+        int r;
+        String s=""; //variable for storing the result
+
+        char dig[]={'0','1'}; //array storing the digits (as characters) in a binary number system
+
+        while(n>0)
+            {
+                r=n%2; //finding remainder by dividing the number by 2
+                s=dig[r]+s; //adding the remainder to the result and reversing at the same time
+                n=n/2;
+            }
+        return s;
+    }
+
+    int countOne(String s) // Function to count no of 1's in binary number
+    {
+        int c = 0, l = s.length();
+        char ch;
+        for(int i=0; i<l; i++)
+        {
+            ch=s.charAt(i);
+            if(ch=='1')
+            {
+                c++;
+            }
+        }
+        return c;
+    }
+
+    public static void main(String args[])
+    {
+        EvilNumber ob = new EvilNumber();
+        Scanner sc = new Scanner(System.in);
+
+        System.out.print("Enter a positive number : ");
+        int n = sc.nextInt();
+
+        String bin = ob.toBinary(n);
+        System.out.println("Binary Equivalent = "+bin);
+
+        int x = ob.countOne(bin);
+        System.out.println("Number of Ones = "+x);
+
+        if(x%2==0)
+            System.out.println(n+" is an Evil Number.");
+        else
+            System.out.println(n+" is Not an Evil Number.");
+    }
+}
+/**
+INPUT : 15
+BINARY EQUIVALENT : 1111
+NO. OF 1’s : 4
+OUTPUT : EVIL NUMBER
+
+Time Complexity = O(n)
+Space Complexity = O(n)
+
+*/

Java/HappyNumber.java

@@ -0,0 +1,42 @@
+public class HappyNumber  
+{     
+    //isHappyNumber() will determine whether a number is happy or not  
+    public static int isHappyNumber(int num){  
+        int rem = 0, sum = 0;  
+
+        //Calculates the sum of squares of digits  
+        while(num > 0){  
+            rem = num%10;  
+            sum = sum + (rem*rem);  
+            num = num/10;  
+        }  
+        return sum;  
+    }  
+
+    public static void main(String[] args) {  
+        int num = 82;  
+        int result = num;  
+
+        while(result != 1 && result != 4){  
+            result = isHappyNumber(result);  
+        }  
+
+        //Happy number always ends with 1  
+        if(result == 1)  
+            System.out.println(num + " is a happy number");  
+        //Unhappy number ends in a cycle of repeating numbers which contains 4  
+        else if(result == 4)  
+            System.out.println(num + " is not a happy number");     
+    }  
+}  
+
+/*
+Time Complexity: O(n)
+Space Complexity: O(n)
+
+32 is a happy number as the process yields 1 as follows
+
+32 + 22 = 13
+12 + 32 = 10
+12 + 02 = 1
+*/

Java/README.md

@@ -1,6 +1,8 @@
 Add links to your code in Alphabetical Order.
 Format: -[Program name](package/name of the file)
 
+-[AbundantNumber](AbundantNumber.java)
+
 -[Anagrams](Anagrams.java)
 
 -[Approximating PI value](Algorithms/approxing_pi.java)
@@ -61,6 +63,8 @@ Format: -[Program name](package/name of the file)
 
 -[Equation of line ,slope ,Distance between 2 points](EqOfLine.java)
 
+-[Evil Number](EvilNumber.java)
+
 -[Fibonacci Search Implementation](Java/Search/FibonacciSearch.java)
 
 -[Find middle element in a Linked List](DataStructures/Middle_element_of_a_Linked_List.java)
@@ -75,6 +79,8 @@ Format: -[Program name](package/name of the file)
 
 -[GCD](Algorithms/GCD_1.java)
 
+-[Happy Number](HappyNumber.java)
+
 -[Heap Sort](Sorting/HeapSort.java)
 
 -[Implement of Rotation of Array](Algorithms/RotateClockwise.java)