2017 Day 06 Complete!

2017/day06/day06.go

@@ -0,0 +1,81 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+)
+
+func main() {
+	inp := StdinToString()
+	pts := strings.Split(inp, "\t")
+	var bnks []int
+	for i := range pts {
+		bnks = append(bnks, Atoi(pts[i]))
+	}
+	process(bnks)
+}
+
+func process(bnks []int) {
+	var states []string
+	var dupe bool
+	var dupeIdx int
+	for !dupe {
+		balance(bnks)
+		newBnks := fmt.Sprint(bnks)
+		for i := range states {
+			if states[i] == newBnks {
+				dupeIdx = i
+				dupe = true
+				break
+			}
+		}
+		states = append(states, newBnks)
+		if dupe {
+			break
+		}
+	}
+	fmt.Println("= Part 1 =")
+	fmt.Println("Duplicate at step:", len(states))
+	fmt.Println("= Part 2 =")
+	fmt.Println("Loop size:", len(states)-dupeIdx-1)
+}
+
+func balance(bnks []int) {
+	var max int
+	for i := range bnks {
+		if bnks[i] > bnks[max] {
+			max = i
+		}
+	}
+	// bnks[max] should be the highest, let's redistribute it
+	var dist, idx int
+	dist, bnks[max], idx = bnks[max], 0, (max+1)%len(bnks)
+	for dist > 0 {
+		bnks[idx]++
+		idx = (idx + 1) % len(bnks)
+		dist--
+	}
+	// Should be balanced now
+}
+
+func StdinToString() string {
+	var input string
+	scanner := bufio.NewScanner(os.Stdin)
+	for scanner.Scan() {
+		input = scanner.Text()
+	}
+	return input
+}
+
+func Atoi(i string) int {
+	var ret int
+	var err error
+	if ret, err = strconv.Atoi(i); err != nil {
+		log.Fatal("Invalid Atoi")
+	}
+	return ret
+}

2017/day06/input

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+4	10	4	1	8	4	9	14	5	1	14	15	0	15	3	5

2017/day06/testinput

@@ -0,0 +1 @@
+0	2	7	0