n-based integer rounding

1.美国程序员面试题

Define the n-based integer rounding of an integer k to be the nearest multiple of n to k. If two multiples of n are equidistant use the greater one. For example
the 4-based rounding of 5 is 4 because 5 is closer to 4 than it is to 8,
the 5-based rounding of 5 is 5 because 5 is closer to 5 that it is to 10,
the 4-based rounding of 6 is 8 because 6 is equidistant from 4 and 8, so the greater one is used, the 13-based rounding of 9 is 13, because 9 is closer to 13 than it is to 0,
Write a function named doIntegerBasedRounding that takes an integer array and rounds all its positive elements using n-based integer rounding.
A negative element of the array is not modified and if n <=0, no elements of the array are modified. Finally you may assume that the array has at least two elements.
Hint: In integer arithmetic, (6/4) * 4 = 4
If you are programming in Java or C#, the function signature is
void doIntegerBasedRounding(int[ ] a, int n) where n is used to do the rounding
If you are programming in C or C++, the function signature is
void doIntegerBasedRounding(int a[ ], int n, int len) where n is used to do the rounding and len is the number of elements in the array a.

2. 测试样例：

3.java实现代码：

package com.zzy;

/**
 * 更多请关注: http://huamaodashu.com
 * Created by hadoopall on 30/07/2018.
 */
public class IntegerBasedRounding {
    public static void main(String[] args) {
//        System.out.println(((double)0/(double)2) *2);

//        int[]a={-1, -2, -3, -4, -5};
//        int n =3;

//        int[]a={-18, 1, 2, 3, 4,5};
//        int n =4;

        int[]a={1, 2, 3, 4, 5};
        int n =100;
        System.out.println(doIntegerBasedRounding(a,n));

    }

    public static int[] doIntegerBasedRounding(int[]a,int n){
        if(n<0){
            return a;
        }else {

            for (int i = 0; i < a.length; i++) {
                if(a[i]<0){
                    a[i]=a[i];
                }else {
                    a[i]= (int) (Math.round(((double)a[i]/(double)n)) * n);

                }
                System.out.println(a[i]);
            }
        }
        return a;
    }
}