京东在线笔试编程题分析

1、计算最小苹果个数

import java.util.Scanner;
public class Main {
    public static int calcuAppleNum(int n) {
        double num = 0.0d;
        int intNum = 0;
        for (int i = 1;; i++) {
            num = fun(i, n, n);
            intNum = (int) num;
            if ((num - intNum) < 10e-9)
                break;
        }
        return intNum;
    }

    public static double fun(int min, double n, int index) {
        if (index <= 1)
            return 1 + n * min;
        return n / (n - 1) * fun(min, n, index - 1) + 1;
    }

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int n = s.nextInt();
        s.close();
        System.out.println(calcuAppleNum(n));
    }
}

2、计算高度

import java.util.Scanner;

public class Main {

    public static int calcuSumHigh(int a[]){
        if(a==null ||a.length <1)
            return 0;
        int sum = 0;
        for(int i=0;i<a.length;i++){
            sum += fun(a[i]) - a[i];
        }
        return sum;
    }

    public static int fun(int n){
        if(n < 1)
            return 0;
        return 2*n+fun(n/2);
    }

    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        int a[] = new int[4];
        int i =0 ;
        while(i<4){
            a[i++] = s.nextInt();
        }
        s.close();
        System.out.println(calcuSumHigh(a));
    }

}