计算整数的2的幂的和

import java.util.ArrayList;
import java.util.List;

public class Mi {
    
    
    public static  int calcn(int n){
    
    
        int len = 32;//sizeof n * 8;
        for(; len > 0;--len){
    
    
            if(0 != (n & (1<< (len-1)))){
    
    
                return len;
            }
        }
        return 0;
    }

    public static List<Integer> calcPower(int A){
    
    
        int n = calcn(A);
        List<Integer> ret = new ArrayList<>();
        for(int i = n - 1; i >= 0; --i){
    
    
            if(!( 1 << i > A)){
    
    
                ret.add(i);
                A -= (1 << i);
                if( A == 0){
    
    
                    break;
                }
            }
        }
        return ret;
    }
    public static void main(String[] args) {
    
    
        int saveA = 114;
        List<Integer> ret = calcPower(saveA);

        System.out.println(saveA + " = " );
        for(int index = ret.size() - 1; index > 0; --index ){
    
    
            System.out.print("2^" + ret.get(index) + " + ");
        }
        System.out.print("2^" + ret.get(0));
        System.out.println();
        int sum = 0;
        for(Integer integer : ret){
    
    
            sum += (1 << integer);
        }
        System.out.println(sum);
    }
}

114 = 
2^1 + 2^4 + 2^5 + 2^6
114