day 7a complete

day7/day 7a/go.mod

@@ -0,0 +1,3 @@
+module PWD
+
+go 1.17

day7/day 7a/main.go

@@ -0,0 +1,90 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"math"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	content := returnContent("../input")
+	//content := returnContent("testInput")
+
+	list := mergeSort((*content), 0, len(*content)-1)
+
+	position := list[len(list)/2]
+	var cost float64
+
+	for i := 0; i < len(list); i++ {
+		cost += math.Abs(float64(position) - float64(list[i]))
+	}
+
+	fmt.Println(cost)
+}
+
+func returnContent(path string) *[]int {
+	//read file and return it as an array of integers
+
+	file, err := os.Open(path)
+	var content []int
+
+	if err != nil {
+		fmt.Println("Unlucky, the file didn't open")
+		return &content
+	}
+	defer file.Close()
+
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		text := strings.Split(scanner.Text(), ",")
+		for _, v := range text {
+			num, _ := strconv.Atoi(v)
+			content = append(content, num)
+		}
+	}
+
+	return &content
+}
+
+//sorting algorithm
+
+func mergeSort(nums []int, start int, end int) []int {
+	if start == end {
+		return []int{nums[start]}
+	}
+
+	var mid int = ((end - start) / 2) + start
+
+	//Assign values back into Left and right
+	left := mergeSort(nums, start, mid)
+	right := mergeSort(nums, mid+1, end)
+
+	var combined []int
+
+	//Pointers for new array
+	leftPointer, rightPointer := 0, 0
+
+	for leftPointer <= len(left)-1 || rightPointer <= len(right)-1 {
+
+		if leftPointer == len(left) {
+			addValue(&combined, right[rightPointer], &rightPointer)
+		} else if rightPointer == len(right) {
+			addValue(&combined, left[leftPointer], &leftPointer)
+		} else {
+			if left[leftPointer] <= right[rightPointer] {
+				addValue(&combined, left[leftPointer], &leftPointer)
+			} else {
+				addValue(&combined, right[rightPointer], &rightPointer)
+			}
+		}
+	}
+	return combined
+}
+
+func addValue(nums *[]int, value int, pointer *int) {
+	*nums = append(*nums, value)
+	*pointer++
+}

day7/day 7a/testInput

@@ -0,0 +1 @@
+3,4,3,1,2