[ADD] Added day 18 solution

18/main.go

@@ -0,0 +1,230 @@
+package main
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+	"time"
+)
+
+const FILE_PATH = "./input.txt"
+const SIZE = 71
+const BYTES = 1024
+
+//const FILE_PATH = "./sample.txt"
+//const SIZE = 7
+//const BYTES = 12
+
+func LoadInput(filename string) ([]string, error) {
+	file, err := os.Open(filename)
+	if err != nil {
+		return nil, err
+	}
+	defer file.Close()
+
+	var lines []string
+	scanner := bufio.NewScanner(file)
+	for scanner.Scan() {
+		lines = append(lines, scanner.Text())
+	}
+
+	if err := scanner.Err(); err != nil {
+		return nil, err
+	}
+
+	return lines, nil
+}
+
+type Vector2 struct {
+	x int
+	y int
+}
+
+type structuredInput = []Vector2
+
+func TransformInput(lines []string) structuredInput {
+	var result = make([]Vector2, len(lines))
+	var numbs []string
+	var x int
+	var y int
+
+	for i, line := range lines {
+		numbs = strings.Split(line, ",")
+		x, _ = strconv.Atoi(numbs[0])
+		y, _ = strconv.Atoi(numbs[1])
+		result[i] = Vector2{x, y}
+	}
+
+	return result
+}
+
+const (
+	EMPTY = iota
+	WALL  = iota
+)
+
+func generateGrid(size int, bytes int, memory []Vector2) [][]int {
+	var result = make([][]int, size)
+
+	for i := 0; i < size; i++ {
+		result[i] = make([]int, size)
+		for j := 0; j < size; j++ {
+			result[i][j] = EMPTY
+		}
+	}
+
+	for i := 0; i < bytes; i++ {
+		result[memory[i].y][memory[i].x] = WALL
+	}
+
+	return result
+}
+
+func printField(field [][]int) {
+	for y := 0; y < len(field); y++ {
+		for x := 0; x < len(field[y]); x++ {
+			if field[y][x] == EMPTY {
+				fmt.Print(".")
+			} else {
+				fmt.Print("#")
+			}
+		}
+		fmt.Println()
+	}
+}
+
+var MOVEMENT = []Vector2{
+	{1, 0},
+	{0, 1},
+	{-1, 0},
+	{0, -1},
+}
+
+func add(a Vector2, b Vector2) Vector2 {
+	return Vector2{a.x + b.x, a.y + b.y}
+}
+
+func isInBounds(position Vector2, bounds Vector2) bool {
+	return position.x >= 0 && position.x < bounds.x && position.y >= 0 && position.y < bounds.y
+}
+
+func Part1(input structuredInput) int {
+	var result = 0
+
+	var start = Vector2{0, 0}
+	var end = Vector2{SIZE - 1, SIZE - 1}
+	var field = generateGrid(SIZE, BYTES, input)
+	var bounds = Vector2{SIZE, SIZE}
+	var score = make([][]int, SIZE)
+	var poss = []Vector2{start}
+	var point Vector2
+	var index int
+	var temp Vector2
+
+	for i := 0; i < SIZE; i++ {
+		score[i] = make([]int, SIZE)
+		for j := 0; j < SIZE; j++ {
+			score[i][j] = -1
+		}
+	}
+	score[start.y][start.x] = 0
+
+	for len(poss) > 0 {
+		point = poss[0]
+		index = 0
+		for i := 1; i < len(poss); i++ {
+			if score[point.y][point.x] > score[poss[i].y][poss[i].x] {
+				point = poss[i]
+				index = i
+			}
+		}
+
+		if point == end {
+			result = score[end.y][end.x]
+			break
+		}
+
+		poss = append(poss[:index], poss[index+1:]...)
+		for i := 0; i < len(MOVEMENT); i++ {
+			temp = add(point, MOVEMENT[i])
+			if isInBounds(temp, bounds) && score[temp.y][temp.x] == -1 && field[temp.y][temp.x] != WALL {
+				score[temp.y][temp.x] = score[point.y][point.x] + 1
+				poss = append(poss, temp)
+			}
+		}
+	}
+
+	return result
+}
+
+func canFinish(field [][]int, start Vector2, finish Vector2, bounds Vector2) bool {
+	var visited = make([][]bool, len(field))
+
+	for i := 0; i < len(visited); i++ {
+		visited[i] = make([]bool, len(field[i]))
+	}
+	var poss = []Vector2{start}
+	var point Vector2
+	var temp Vector2
+
+	for len(poss) > 0 {
+		point = poss[0]
+		poss = poss[1:]
+		for i := 0; i < 4; i++ {
+			temp = add(point, MOVEMENT[i])
+			if isInBounds(temp, bounds) && !visited[temp.y][temp.x] && field[temp.y][temp.x] != WALL {
+				poss = append(poss, temp)
+				visited[temp.y][temp.x] = true
+				if temp == finish {
+					return true
+				}
+			}
+		}
+	}
+	return false
+}
+
+func Part2(input structuredInput) int {
+	var result = 0
+
+	var start = Vector2{0, 0}
+	var end = Vector2{SIZE - 1, SIZE - 1}
+	var field = generateGrid(SIZE, BYTES, input)
+	var bounds = Vector2{SIZE, SIZE}
+	i := BYTES
+
+	for canFinish(field, start, end, bounds) {
+		field[input[i].y][input[i].x] = WALL
+		i++
+	}
+	i -= 1
+
+	fmt.Printf("%d,%d\n", input[i].x, input[i].y)
+
+	return result
+}
+
+func main() {
+	var start time.Time
+	var elapsed time.Duration = 0
+	input, err := LoadInput(FILE_PATH)
+	if err != nil {
+		fmt.Println("Error loading input:", err)
+		return
+	}
+
+	structuredInput := TransformInput(input)
+	fmt.Println("Structured Input:", structuredInput)
+
+	start = time.Now()
+	fmt.Println("Solution Part 1: ", Part1(structuredInput))
+	elapsed = time.Since(start)
+	fmt.Printf("Part 1 took %s\n", elapsed)
+
+	start = time.Now()
+	fmt.Println("Solution Part 2: ", Part2(structuredInput))
+	elapsed = time.Since(start)
+	fmt.Printf("Part 2 took %s\n", elapsed)
+}

18/sample.txt

@@ -0,0 +1,25 @@
+5,4
+4,2
+4,5
+3,0
+2,1
+6,3
+2,4
+1,5
+0,6
+3,3
+2,6
+5,1
+1,2
+5,5
+2,5
+6,5
+1,4
+0,4
+6,4
+1,1
+6,1
+1,0
+0,5
+1,6
+2,0