CSC1109_Tutorials/Exam/FIB.java

package Exam;

import java.util.*;

public class FIB {
    public static int fib(int a){
        if(a == 0 || a == 1) return a;
        return fib(a-1) + fib(a-2);
    }

    public static int fac(int a){
        if (a <= 1) return a;
        else return a * fac(a - 1);
    }

    public static int[] mergesort(int[] arr){
        if (arr.length <= 1) {
            return arr;
        }

        int mid = arr.length >> 1;

        int[] left = new int[mid];
        int[] right = new int[arr.length - mid];

        for (int i = 0; i < mid; i++){
            left[i] = arr[i];
        }
        for (int i = mid; i < arr.length; i++){
            right[i - mid] = arr[i];
        }
        left = mergesort(left);
        right = mergesort(right);

        return merge(left, right);
    }

    public static int[] merge(int[] a, int[] b){
        int aindex = 0, bindex = 0;
        int [] result = new int[a.length + b.length];
        int aSize = a.length, bSize = b.length;

        while (aindex < a.length && bindex < bSize){
            if (a[aindex] < b[bindex]){
                result[aindex + bindex] = a[aindex];
                aindex++;
            }
            else{
                result[aindex + bindex] = b[bindex];
                bindex++;
            }
        }

        while (aindex < aSize){
            result[aindex + bindex] = a[aindex];
            aindex++;
        }

        while (bindex < bSize){
            result[aindex + bindex] = b[bindex];
            bindex++;
        }

        return result;
    }

    public static ArrayList<Integer> mergesort(ArrayList<Integer> arr){
        if (arr.size() <= 1) {
            return arr;
        }

        int mid = arr.size() >> 1;

        ArrayList<Integer> left = new ArrayList<>();
        ArrayList<Integer> right = new ArrayList<>();

        for (int i = 0; i < mid; i++){
            left.add(arr.get(i));
        }
        for (int i = mid; i < arr.size(); i++){
            right.add(arr.get(i));
        }
        left = mergesort(left);
        right = mergesort(right);

        return merge(left, right);
    }

    public static ArrayList<Integer> merge(ArrayList<Integer> a, ArrayList<Integer> b){
        ArrayList<Integer> c = new ArrayList<>();
        int aindex = 0, bindex = 0;
        int aSize = a.size(), bSize = b.size();

        while (aindex < aSize && bindex < bSize){
            if (a.get(aindex) < b.get(bindex)){
                c.add(a.get(aindex));
                aindex++;
            }
            else{
                c.add(b.get(bindex));
                bindex++;
            }
        }

        while (aindex < aSize){
            c.add(a.get(aindex));
            aindex++;
        }

        while (bindex < bSize){
            c.add(b.get(bindex));
            bindex++;
        }

        return c;
    }

    public static int BSearc(int[] arr, int num){
        int low = 0, high = arr.length;
        while (low <= high){
            int mid = (low + high) >> 1;
            if (arr[mid] == num) return mid;
            else if (arr[mid] < num) low = mid + 1;
            else high = mid - 1;
        }
        return -1;
    }

    public static void main(String[] args) {
        int[] arr = {1, 2, 3, 4, 5, 6, 7, 8, 9,10};
        int num = 4;
        System.out.println(BSearc(arr, num));
    }
}
class person{
    private String name;
    private int age;

    public person(String name, int age){
        System.out.println("Person constructor");
        this.name = name;
        this.age = age;
    }

    public person(String name){
        this(name, 0);
    }

    public person(int age){
        this("John", age);
    }

    public String getName(){
        return this.name;
    }
    public void setName(String name) {
        this.name = name;
    }

    public int getAge(){
        return this.age;
    }
    public void setAge(int age) {
        this.age = age;
    }
}

class Student extends person{
    private int GPA;
    private double height;
    public Student(){
        this("John", 0, 0);
    }
    public Student(String name, int age, int GPA){
        super(name, age);
        this.GPA = GPA;
    }
    public Student(double height){
        this("John", 0, 0);
        this.height = height;
        System.out.println("Student height: " + height);
    }

    private Student(String name, int GPA){
        this(name, 0, GPA);
    }

    public Student(int GPA, int age, String name){
        this(name, age, GPA);
    }

    public Student(int age, String name){
        this(name, age, 0);
    }

    public void setAge(int age){
        System.out.printf("Student age: %d \n", age);
        super.setAge(age);
    }
    public static void main(String... args){
        var s = new Student(3);
        System.out.println(s.getAge());
    }
}

class myexception extends Exception{
    public myexception(String message){
        super(message);
    }
}