• 8 Posts
  • 35 Comments
Joined 2 years ago
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Cake day: September 17th, 2023

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  • I have mixed feelings about that company. They have some interesting things “going against the flow” like ditching the cloud and going back to on prem, hating on microservices, advocating against taking money from VCs, and now hiring juniors. On the other hand, the guy is a Musk fanboy and they push some anti-DEI bullshit. Also he’s a TypeScript hater for some reason…




  • Go

    Using a map to store u|v relations. Part 2 sorting with a custom compare function worked very nicely

    spoiler
    func main() {
    	file, _ := os.Open("input.txt")
    	defer file.Close()
    	scanner := bufio.NewScanner(file)
    
    	mapPages := make(map[string][]string)
    	rulesSection := true
    	middleSumOk := 0
    	middleSumNotOk := 0
    
    	for scanner.Scan() {
    		line := scanner.Text()
    		if line == "" {
    			rulesSection = false
    			continue
    		}
    
    		if rulesSection {
    			parts := strings.Split(line, "|")
    			u, v := parts[0], parts[1]
    			mapPages[u] = append(mapPages[u], v)
    		} else {
    			update := strings.Split(line, ",")
    			isOk := true
    
    			for i := 1; i < len(update); i++ {
    				u, v := update[i-1], update[i]
    				if !slices.Contains(mapPages[u], v) {
    					isOk = false
    					break
    				}
    			}
    
    			middlePos := len(update) / 2
    			if isOk {
    				middlePage, _ := strconv.Atoi(update[middlePos])
    				middleSumOk += middlePage
    			} else {
    				slices.SortFunc(update, func(u, v string) int {
    					if slices.Contains(mapPages[u], v) {
    						return -1
    					} else if slices.Contains(mapPages[v], u) {
    						return 1
    					}
    					return 0
    				})
    				middlePage, _ := strconv.Atoi(update[middlePos])
    				middleSumNotOk += middlePage
    			}
    		}
    	}
    
    	fmt.Println("Part 1:", middleSumOk)
    	fmt.Println("Part 2:", middleSumNotOk)
    }
    


  • Go

    Just a bunch of ifs and bounds checking. Part 2 was actually simpler.

    Code
    func part1(W [][]rune) {
    	m := len(W)
    	n := len(W[0])
    	xmasCount := 0
    
    	for i := 0; i < m; i++ {
    		for j := 0; j < n; j++ {
    			if W[i][j] != 'X' {
    				continue
    			}
    			if j < n-3 && W[i][j+1] == 'M' && W[i][j+2] == 'A' && W[i][j+3] == 'S' {
    				// Horizontal left to right
    				xmasCount++
    			}
    			if j >= 3 && W[i][j-1] == 'M' && W[i][j-2] == 'A' && W[i][j-3] == 'S' {
    				// Horizontal right to left
    				xmasCount++
    			}
    			if i < m-3 && W[i+1][j] == 'M' && W[i+2][j] == 'A' && W[i+3][j] == 'S' {
    				// Vertical up to down
    				xmasCount++
    			}
    			if i >= 3 && W[i-1][j] == 'M' && W[i-2][j] == 'A' && W[i-3][j] == 'S' {
    				// Vertical down to up
    				xmasCount++
    			}
    			if j < n-3 && i < m-3 && W[i+1][j+1] == 'M' && W[i+2][j+2] == 'A' && W[i+3][j+3] == 'S' {
    				// Diagonal left to right and up to down
    				xmasCount++
    			}
    			if j >= 3 && i < m-3 && W[i+1][j-1] == 'M' && W[i+2][j-2] == 'A' && W[i+3][j-3] == 'S' {
    				// Diagonal right to left and up to down
    				xmasCount++
    			}
    			if j < n-3 && i >= 3 && W[i-1][j+1] == 'M' && W[i-2][j+2] == 'A' && W[i-3][j+3] == 'S' {
    				// Diagonal left to right and down to up
    				xmasCount++
    			}
    			if j >= 3 && i >= 3 && W[i-1][j-1] == 'M' && W[i-2][j-2] == 'A' && W[i-3][j-3] == 'S' {
    				// Diagonal right to left and down to up
    				xmasCount++
    			}
    		}
    	}
    
    	fmt.Println(xmasCount)
    }
    
    func part2(W [][]rune) {
    	m := len(W)
    	n := len(W[0])
    	xmasCount := 0
    
    	for i := 0; i <= m-3; i++ {
    		for j := 0; j <= n-3; j++ {
    			if W[i+1][j+1] != 'A' {
    				continue
    			}
    			if W[i][j] == 'M' && W[i][j+2] == 'M' && W[i+2][j] == 'S' && W[i+2][j+2] == 'S' {
    				xmasCount++
    			} else if W[i][j] == 'M' && W[i][j+2] == 'S' && W[i+2][j] == 'M' && W[i+2][j+2] == 'S' {
    				xmasCount++
    			} else if W[i][j] == 'S' && W[i][j+2] == 'S' && W[i+2][j] == 'M' && W[i+2][j+2] == 'M' {
    				xmasCount++
    			} else if W[i][j] == 'S' && W[i][j+2] == 'M' && W[i+2][j] == 'S' && W[i+2][j+2] == 'M' {
    				xmasCount++
    			}
    		}
    	}
    
    	fmt.Println(xmasCount)
    }
    
    func main() {
    	file, _ := os.Open("input.txt")
    	defer file.Close()
    	scanner := bufio.NewScanner(file)
    
    	var W [][]rune
    	for scanner.Scan() {
    		line := scanner.Text()
    		W = append(W, []rune(line))
    	}
    
    	part1(W)
    	part2(W)
    }
    


  • Go

    Part 1, just find the regex groups, parse to int, and done.

    Part 1
    func part1() {
    	file, _ := os.Open("input.txt")
    	defer file.Close()
    	scanner := bufio.NewScanner(file)
    
    	re := regexp.MustCompile(`mul\(([0-9]{1,3}),([0-9]{1,3})\)`)
    	product := 0
    
    	for scanner.Scan() {
    		line := scanner.Text()
    		submatches := re.FindAllStringSubmatch(line, -1)
    
    		for _, s := range submatches {
    			a, _ := strconv.Atoi(s[1])
    			b, _ := strconv.Atoi(s[2])
    			product += (a * b)
    		}
    	}
    
    	fmt.Println(product)
    }
    

    Part 2, not so simple. Ended up doing some weird hack with a map to check if the multiplication was enabled or not. Also instead of finding regex groups I had to find the indices, and then interpret what those mean… Not very readable code I’m afraid

    Part2
    func part2() {
    	file, _ := os.Open("input.txt")
    	defer file.Close()
    	scanner := bufio.NewScanner(file)
    
    	mulRE := regexp.MustCompile(`mul\(([0-9]{1,3}),([0-9]{1,3})\)`)
    	doRE := regexp.MustCompile(`do\(\)`)
    	dontRE := regexp.MustCompile(`don't\(\)`)
    	product := 0
    	enabled := true
    
    	for scanner.Scan() {
    		line := scanner.Text()
    		doIndices := doRE.FindAllStringIndex(line, -1)
    		dontIndices := dontRE.FindAllStringIndex(line, -1)
    		mulSubIndices := mulRE.FindAllStringSubmatchIndex(line, -1)
    
    		mapIndices := make(map[int]string)
    		for _, do := range doIndices {
    			mapIndices[do[0]] = "do"
    		}
    		for _, dont := range dontIndices {
    			mapIndices[dont[0]] = "dont"
    		}
    		for _, mul := range mulSubIndices {
    			mapIndices[mul[0]] = "mul"
    		}
    
    		nextMatch := 0
    
    		for i := 0; i < len(line); i++ {
    			val, ok := mapIndices[i]
    			if ok && val == "do" {
    				enabled = true
    			} else if ok && val == "dont" {
    				enabled = false
    			} else if ok && val == "mul" {
    				if enabled {
    					match := mulSubIndices[nextMatch]
    					a, _ := strconv.Atoi(string(line[match[2]:match[3]]))
    					b, _ := strconv.Atoi(string(line[match[4]:match[5]]))
    					product += (a * b)
    				}
    				nextMatch++
    			}
    		}
    	}
    
    	fmt.Println(product)
    }
    











  • This would be the best way. Unfortunately they made it the other way around. A screen at the door shows the code, and you scan it with the app.

    In my previous gym the code was on the app, but I’m not sure anymore if it was static or it changed over time. But the reader on the door was awful, I used to spend a good 3 minutes trying different angles with my phone to make it recognize the code.