코딩테스트 준비 일지

• 응시 사이트 : 해커랭크

• 문제 : Plus Minus

• 난이도 : 하

문제

Given an array of integers, calculate the ratios of its elements that are positive, negative, and zero. Print the decimal value of each fraction on a new line with

places after the decimal.

Note: This challenge introduces precision problems. The test cases are scaled to six decimal places, though answers with absolute error of up to 10^(-4), are acceptable.

Example

arr = [1,1,0-1,-1]

There are n = 5 elements, two positive, two negative and one zero. Their ratios are 2/5 = 0.400000 , 2/5 = 0.400000 , and 1/5 = 0.200000. Results are printed as:

0.400000
0.400000
0.200000

Function Description

Complete the plusMinus function in the editor below.

plusMinus has the following parameter(s):

• int arr[n]: an array of integers

Print
Print the ratios of positive, negative and zero values in the array. Each value should be printed on a separate line with

digits after the decimal. The function should not return a value.

Input Format

The first line contains an integer,

, the size of the array.
The second line contains space-separated integers that describe

Constraints

• 0 < n <= 100

• - 100 <= arr[i] <= 100

Output Format

Print the following lines, each to decimals:

1. proportion of positive values

2. proportion of negative values

3. proportion of zeros

Sample Input

STDIN           Function
-----           --------
6               arr[] size n = 6
-4 3 -9 0 4 1   arr = [-4, 3, -9, 0, 4, 1]

Sample Output

0.500000
0.333333
0.166667

Explanation

There are positive numbers, negative numbers, and zero in the array.
The proportions of occurrence are positive: 3/6 = 0.500000 , negative: 2/6 = 0.333333 and zeros: 1/6 = 0.166667

문제 풀이 접근

뭔가 문제가 영어다보니, 쉬운 문제도 어렵게 보이는 듯한 그런 느낌이 있다.
하지만, 이 문제는 아래와 같다.
1. n 개 정수 던져줄게
2. 양수 / 전체 , 음수 / 전체, 0 / 전체 이렇게 나눠서 값 출력해.

그래서 던져주는대로, 갯수를 먼저 세고, 양의 정수, 음의 정수, 0 의 값을 비율로 출력했다.
출력까지 하는줄 몰랐는데, 출력하니 All Case Pass 였다.

작성 코드 ( C# )

using System.CodeDom.Compiler;
using System.Collections.Generic;
using System.Collections;
using System.ComponentModel;
using System.Diagnostics.CodeAnalysis;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Runtime.Serialization;
using System.Text.RegularExpressions;
using System.Text;
using System;
class Result
{/*
 * Complete the 'plusMinus' function below.
 *
 * The function accepts INTEGER_ARRAY arr as parameter.
 */
public static List<double> ratio = new List<double>();public static void plusMinus(List<int> arr)
{
double count = arr.Count;
double posiCount = arr.FindAll(rhs => rhs > 0).Count;
double NegaCount = arr.FindAll(rhs => rhs < 0).Count;
double ZeroCount = arr.FindAll(rhs => rhs == 0).Count;ratio.Add(posiCount/count);
ratio.Add(NegaCount/count);
ratio.Add(ZeroCount/count);}}class Solution
{
public static void Main(string[] args)
{
int n = Convert.ToInt32(Console.ReadLine().Trim());    List<int> arr = Console.ReadLine().TrimEnd().Split(' ').ToList().Select(arrTemp => Convert.ToInt32(arrTemp)).ToList();Result.plusMinus(arr);
var ratio = Result.ratio;for(int i = 0; i < ratio.Count; ++i)
{
Console.WriteLine(ratio[i]);
}}}