[Hacker Rank]: Plus Minus solved ✓

Author: Gonzalo Diaz

docs/hackerrank/warmup/plusMinus.md

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+# [Plus Minus](https://www.hackerrank.com/challenges/plus-minus)
+
+Difficulty: #easy
+Category: #warmup
+
+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 6 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:
+
+```text
+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 $ 6 $ digits after
+the decimal. The function should not return a value.
+
+## Input Format
+
+The first line contains an integer, `n`, the size of the array.
+The second line contains `n` space-separated integers that describe `arr[n]`.
+
+## Constraints
+
+$ 0 < n \leq 100 $ \
+$ -100 \leq arr[i] \leq 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
+
+```text
+STDIN           Function
+-----           --------
+6               arr[] size n = 6
+-4 3 -9 0 4 1   arr = [-4, 3, -9, 0, 4, 1]
+```
+
+## Sample Output
+
+```text
+0.500000
+0.333333
+0.166667
+```
+
+## Explanation
+
+There are $ 3 $ positive numbers, negative numbers, and $ 1 $ 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 $.

src/pkg/hackerrank/warmup/plusMinus.go

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+/**
+ * @link Problem definition [[docs/hackerrank/warmup/plusMinus.md]]
+ */
+
+package hackerrank
+
+import (
+	"fmt"
+	"strings"
+
+	utils "gon.cl/algorithm-exercises/src/utils"
+)
+
+func PlusMinus(arr []int) string {
+
+	positives := 0
+	negatives := 0
+	zeros := 0
+
+	for i := 0; i < len(arr); i += 1 {
+		var num = arr[i]
+
+		if num > 0 {
+			positives += 1
+		} else if num < 0 {
+			negatives += 1
+		} else if num == 0 {
+			zeros += 1
+		}
+	}
+
+	result := []string{}
+
+	result = append(result, fmt.Sprintf("%.6f", float64(positives)/float64(len(arr))))
+	result = append(result, fmt.Sprintf("%.6f", float64(negatives)/float64(len(arr))))
+	result = append(result, fmt.Sprintf("%.6f", float64(zeros)/float64(len(arr))))
+
+	answer := strings.Join(result, "\n")
+
+	utils.Info("PlusMinus answer => %s", answer)
+
+	return answer
+}

src/pkg/hackerrank/warmup/plusMinus_test.go

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+package hackerrank
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestPlusMinus(t *testing.T) {
+
+	expectedSolution := strings.Join([]string{"0.500000", "0.333333", "0.166667"}, "\n")
+	input := []int{-4, 3, -9, 0, 4, 1}
+
+	testname := fmt.Sprintf("PlusMinus(%d) => %v \n", input, expectedSolution)
+	t.Run(testname, func(t *testing.T) {
+
+		ans := PlusMinus(input)
+		assert.Equal(t, expectedSolution, ans)
+	})
+}