[Hacker Rank]: Mini-Max Sum solved ✓

Author: Gonzalo Diaz

docs/hackerrank/warmup/miniMaxSum.md

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+# [Mini-Max Sum](https://www.hackerrank.com/challenges/mini-max-sum)
+
+Difficulty: #easy
+Category: #warmup
+
+Given five positive integers, find the minimum and maximum values
+that can be calculated by summing exactly four of the five integers.
+Then print the respective minimum and maximum values as a single line
+of two space-separated long integers.
+
+## Example
+
+$ arr = [1, 3, 5, 7, 9] $
+The minimum sum is $ 1 + 3 + 5 + 7 = 16 $ and the maximum sum
+is $ 3 + 5 + 7 + 9 = 24 $. The function prints
+
+```text
+16 24
+```
+
+## Function Description
+
+Complete the miniMaxSum function in the editor below.
+miniMaxSum has the following parameter(s):
+
+- arr: an array of $ 5 $ integers
+
+## Print
+
+Print two space-separated integers on one line: the minimum sum and
+the maximum sum of 4 of 5 elements.
+
+## Input Format
+
+A single line of five space-separated integers.
+
+## Constraints
+
+$ 1 \leq arra[i] \leq 10^9 $
+
+## Output Format
+
+Print two space-separated long integers denoting the respective minimum
+and maximum values that can be calculated by summing exactly four of the
+five integers. (The output can be greater than a 32 bit integer.)
+
+## Sample Input
+
+```text
+1 2 3 4 5
+```
+
+## Sample Output
+
+```text
+10 14
+```
+
+## Explanation
+
+The numbers are $ 1, 2, 3, 4, $ and $ 5 $. Calculate the following sums using
+four of the five integers:
+
+1. Sum everything except $ 1 $, the sum is $ 2 + 3 + 4 + 5 = 14 $.
+2. Sum everything except $ 2 $, the sum is $ 1 + 3 + 4 + 5 = 13 $.
+3. Sum everything except $ 3 $, the sum is $ 1 + 2 + 4 + 5 = 12 $.
+4. Sum everything except $ 4 $, the sum is $ 1 + 2 + 3 + 5 = 11 $.
+5. Sum everything except $ 5 $, the sum is $ 1 + 2 + 3 + 4 = 10 $.
+
+**Hints**: Beware of integer overflow! Use 64-bit Integer.

src/pkg/hackerrank/warmup/miniMaxSum.go

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+/**
+ * @link Problem definition [[docs/hackerrank/warmup/miniMaxSum.md]]
+ */
+
+package hackerrank
+
+import (
+	"errors"
+	"fmt"
+)
+
+func MiniMaxSum(arr []int) (string, error) {
+	if len(arr) == 0 {
+		return "", errors.New("empty input")
+	}
+
+	sum := 0
+	min := arr[0]
+	max := arr[1]
+
+	for i := 0; i < len(arr); i++ {
+		num := arr[i]
+		sum += num
+
+		if num < min {
+			min = num
+		}
+
+		if num > max {
+			max = num
+		}
+	}
+
+	return fmt.Sprintf("%d %d", sum-max, sum-min), nil
+}

src/pkg/hackerrank/warmup/miniMaxSum_test.go

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+package hackerrank
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestMiniMaxSumBorderCase(t *testing.T) {
+	expectedSolution := []int{1, 1}
+	input := []int{}
+
+	testname := fmt.Sprintf("MiniMaxSum(%v) => %d \n", input, expectedSolution)
+	t.Run(testname, func(t *testing.T) {
+
+		_, err := MiniMaxSum(input)
+		assert.Error(t, err)
+	})
+}
+
+func TestMiniMaxSum(t *testing.T) {
+	var tests = []struct {
+		input []int
+		want  string
+	}{
+		{input: []int{1, 2, 3, 4, 5}, want: "10 14"},
+		{input: []int{5, 4, 3, 2, 1}, want: "10 14"},
+	}
+
+	for _, tt := range tests {
+
+		testname := fmt.Sprintf("MiniMaxSum(%v) => %s", tt.input, tt.want)
+		t.Run(testname, func(t *testing.T) {
+			ans, _ := MiniMaxSum(tt.input)
+			assert.Equal(t, tt.want, ans)
+		})
+	}
+}