day 10

10/main.go

@@ -0,0 +1,128 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"sort"
+	"strconv"
+	"time"
+)
+
+func mustAtoi(line string) int {
+	i, _ := strconv.Atoi(line)
+	return i
+}
+
+func main() {
+	start := time.Now()
+	partOne()
+	duration := time.Since(start)
+	partTwo()
+	duration2 := time.Since(start)
+	fmt.Printf("p1: %s, p2: %s\n", duration, duration2-duration)
+}
+
+func makeScanner(test bool) *bufio.Scanner {
+	var f *os.File
+	if test {
+		f, _ = os.Open("inputs/testinput")
+	} else {
+		f, _ = os.Open("inputs/input")
+	}
+	reader := bufio.NewReader(f)
+	return bufio.NewScanner(reader)
+}
+
+type parsed struct {
+	errorChar         rune
+	missingkeys       []rune
+	autocompleteTotal int
+}
+
+func pop(stack []rune) (rune, []rune) {
+	pop := stack[len(stack)-1]
+	return pop, stack[:len(stack)-1]
+}
+
+func parseLine(line string) parsed {
+	stack := []rune{}
+	for _, v := range line {
+		var p rune
+		switch v {
+		case '[', '{', '<', '(':
+			stack = append(stack, v)
+		case '>':
+			p, stack = pop(stack)
+			if p != '<' {
+				return parsed{errorChar: v}
+			}
+		case ')':
+			p, stack = pop(stack)
+			if p != '(' {
+				return parsed{errorChar: v}
+			}
+		case ']':
+			p, stack = pop(stack)
+			if p != '[' {
+				return parsed{errorChar: v}
+			}
+		case '}':
+			p, stack = pop(stack)
+			if p != '{' {
+				return parsed{errorChar: v}
+			}
+		}
+	}
+	if len(stack) != 0 {
+		return parsed{missingkeys: stack}
+	}
+	return parsed{}
+}
+
+func partOne() {
+	scanner := makeScanner(false)
+
+	sum := 0
+	for scanner.Scan() {
+		result := parseLine(scanner.Text())
+		switch result.errorChar {
+		case ')':
+			sum += 3
+		case ']':
+			sum += 57
+		case '}':
+			sum += 1197
+		case '>':
+			sum += 25137
+		}
+	}
+	fmt.Println(sum)
+}
+
+func partTwo() {
+	scanner := makeScanner(false)
+
+	scores := []int{}
+	for scanner.Scan() {
+		result := parseLine(scanner.Text())
+		if result.errorChar == 0 {
+			for i := len(result.missingkeys) - 1; i >= 0; i-- {
+				result.autocompleteTotal *= 5
+				switch result.missingkeys[i] {
+				case '(':
+					result.autocompleteTotal += 1
+				case '[':
+					result.autocompleteTotal += 2
+				case '{':
+					result.autocompleteTotal += 3
+				case '<':
+					result.autocompleteTotal += 4
+				}
+			}
+			scores = append(scores, result.autocompleteTotal)
+		}
+	}
+	sort.Ints(scores)
+	fmt.Println(scores[(len(scores) / 2)])
+}