feat(angch/2024-05): Initial

angch/2024-05/main.go

@@ -0,0 +1,121 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+func day5(file string) (part1, part2 int) {
+	f, err := os.Open(file)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer f.Close()
+
+	scanner := bufio.NewScanner(f)
+	rules := make(map[int][]int)
+	printbefore := make(map[int][]int)
+	for scanner.Scan() {
+		t := scanner.Text()
+		if t == "" {
+			break
+		}
+		p1, p2 := 0, 0
+		fmt.Sscanf(t, "%d|%d", &p1, &p2)
+
+		_, ok := rules[p1]
+		if !ok {
+			rules[p1] = make([]int, 0)
+		}
+		rules[p1] = append(rules[p1], p2)
+
+		_, ok = printbefore[p2]
+		if !ok {
+			printbefore[p2] = make([]int, 0)
+		}
+		printbefore[p2] = append(printbefore[p2], p1)
+	}
+	// log.Println(rules)
+
+	updates := [][]int{}
+	for scanner.Scan() {
+		t := scanner.Text()
+		f := strings.Split(t, ",")
+		u := []int{}
+		for _, v := range f {
+			i, err := strconv.Atoi(v)
+			if err == nil {
+				u = append(u, i)
+			}
+		}
+		updates = append(updates, u)
+	}
+	// log.Println(updates)
+
+	for _, update := range updates {
+		ispart2 := false
+	a:
+		printed := make(map[int]int)
+		good := true
+
+		toprint := make(map[int]bool)
+		for _, v := range update {
+			toprint[v] = true
+		}
+		swap1, swap2 := 0, 0
+		page := 0
+	b:
+		for k1, v := range update {
+			if rules[v] != nil {
+				for _, p := range rules[v] {
+					if !toprint[p] {
+						continue
+					}
+					if printed[p] > 0 {
+						swap1 = printed[p]
+						swap2 = k1
+						good = false
+						break b
+					}
+				}
+			}
+			page++
+			printed[v] = page
+		}
+		if good {
+			mid := len(update) / 2
+			if !ispart2 {
+				part1 += update[mid]
+			} else {
+				part2 += update[mid]
+			}
+		} else {
+			// part2 reorder
+			swap1--
+			// log.Println(swap1, swap2)
+			update[swap1], update[swap2] = update[swap2], update[swap1]
+			// log.Println(update)
+			ispart2 = true
+			goto a // Meh
+		}
+	}
+
+	return
+}
+
+func main() {
+	log.SetFlags(log.Lshortfile | log.LstdFlags)
+	t1 := time.Now()
+	part1, part2 := day5("test.txt")
+	fmt.Println(part1, part2)
+	if part1 != 143 || part2 != 123 {
+		log.Fatal("Test failed ", part1, part2)
+	}
+	fmt.Println(day5("input.txt"))
+	fmt.Println("Elapsed time:", time.Since(t1))
+}

angch/2024-05/test.txt

@@ -0,0 +1,28 @@
+47|53
+97|13
+97|61
+97|47
+75|29
+61|13
+75|53
+29|13
+97|29
+53|29
+61|53
+97|53
+61|29
+47|13
+75|47
+97|75
+47|61
+75|61
+47|29
+75|13
+53|13
+
+75,47,61,53,29
+97,61,53,29,13
+75,29,13
+75,97,47,61,53
+61,13,29
+97,13,75,29,47