1 files changed, 57 insertions, 0 deletions
diff --git a/2021/07/first.go b/2021/07/first.go
new file mode 100644
index 0000000..c4692ec
--- /dev/null
+++ b/2021/07/first.go
@@ -0,0 +1,57 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"sort"
+	"strconv"
+)
+
+func abs(a int) int {
+	if a > 0 {
+		return a
+	} else {
+		return -a
+	}
+}
+
+func splitOnCommas(data []byte, atEOF bool) (advance int, token []byte, err error) {
+	var ch byte
+	for advance, ch = range data {
+		if ch < '0' || ch > '9' {
+			break
+		}
+	}
+	if advance > 0 {
+		token = data[0:advance]
+		advance++ // skip the comma
+	}
+	return
+}
+
+func main() {
+	positions := make([]int, 0)
+
+	s := bufio.NewScanner(os.Stdin)
+	s.Split(splitOnCommas)
+	for s.Scan() {
+		n, _ := strconv.Atoi(s.Text())
+		positions = append(positions, n)
+	}
+
+	sort.Ints(positions)
+	medianPosition := len(positions) / 2
+	median := 0
+	if len(positions)%2 == 0 {
+		median = positions[medianPosition]
+	} else {
+		median = (positions[medianPosition] + positions[medianPosition+1]) / 2
+	}
+
+	total := 0
+	for _, i := range positions {
+		total += abs(i - median)
+	}
+	fmt.Println(total)
+}