GFG recursion practice 01

 package com.company;

public class CWR_Gfg_practice {

//    recursion example
    public static int test(int n){
        if( n == 0){
            return 0;
        }
        int a = 1 + test(n / 2);
        System.out.println(a);
        return a;
    }

    //    Calculating the value of log n base 2.
    public static int log2(int n) {
        if (n == 0) {
            return -1;
        }
        int count = 0;
        while (n != 1) {
            n = n >> 1;
            count++;
        }
        return count;
    }

    //Given a number N, find the most significant set bit in the given number
    public static int findMostSignificant(int n) {
        int a = log2(n);
        return (int) Math.pow(2, a);
    }

//Given a number N, the task is to find the XOR of all numbers from 1 to N
public static int xorUptoN(int n){
        int res = 0;
        for(int i = 1; i<n+1; i++){
            res = res ^ i;
        }
        return res;
}

//Given an array arr[] of N positive elements. The task is to find the Maximum AND Value generated by any pair of the element from the array.

    public static int maximumAnd(int [] arr, int n){
        int maxi = 0;
        for(int i = 0; i<n; i++){
            for(int j = i + 1; j<n; j++){
                maxi = Math.max(arr[i] & arr[j], maxi);
            }
        }
        return maxi;
    }

    public static void main(String[] args) {
//        System.out.println(xorUptoN(6));
//        int [] a ={4, 8, 16, 12};
//        System.out.println(maximumAnd(a,4));
test(10);
        System.out.println(test(10));
    }
}