Performance

Basics This is a wercker Test.

Basics This is a wercker Test.

Basics Hello folks. This will be a quick post about how to do CORS with jQuery, Gin in Go with a very simple ajax GET and Json. I’m choosing JSON here because basically I don’t really like JSONP. And actually, it’s not very complicated to do CORS, it’s just hidden enough so that it doesn’t become transparent. First, what is CORS? It’s Cross-Platform Resource Sharing. It has been invented so that without your explicit authorization in the header of a request, Javascript can’t reach outside of your domain and be potentially harmful to your visitors. ...

Hello folks. I wanted to share with you my tale of working through the problems with Advent Of Code. It is a nice tale and there are a few things I learned from it, especially in Go, since I used that solve all of the problems. So, let’s get started. Solving the problems The most important lesson I learned while doing these exercises was, how to solve these problems. A couple of them were simple enough to not have to over think it, but most of them got very tricky. I could have gone with a brute force attempt, but as we see later, that wasn’t always a very good solution. And people who used that, actually just got lucky finding their solutions. ...

Hello Folks. Today I would like to share with you my little tale of refactoring my solution to Advent Of Code Day 13. It’s a lovely tale of action, adventure, drama, and comedy. Let’s being with my first iteration of the problem. package main import ( "bufio" "fmt" "math" "os" "strconv" "strings" "github.com/skarlso/goutils/arrayutils" ) var seatingCombinations = make([][]string, 0) var table = make(map[string][]map[string]int) var keys = make([]string, 0) //Person a person type Person struct { // neighbour *Person name string like int } func main() { file, _ := os.Open("input.txt") defer file.Close() scanner := bufio.NewScanner(file) for scanner.Scan() { line := scanner.Text() split := strings.Split(line, " ") like, _ := strconv.Atoi(split[3]) //If lose -> * -1 if split[2] == "lose" { like *= -1 } table[split[0]] = append(table[split[0]], map[string]int{strings.Trim(split[10], "."): like}) if !arrayutils.ContainsString(keys, split[0]) { keys = append(keys, split[0]) } } generatePermutation(keys, len(keys)) fmt.Println("Best seating efficiency:", calculateSeatingEfficiancy()) } func generatePermutation(s []string, n int) { if n == 1 { news := make([]string, len(s)) copy(news, s) seatingCombinations = append(seatingCombinations, news) } for i := 0; i < n; i++ { s[i], s[n-1] = s[n-1], s[i] generatePermutation(s, n-1) s[i], s[n-1] = s[n-1], s[i] } } func calculateSeatingEfficiancy() int { bestSeating := math.MinInt64 for _, v := range seatingCombinations { calculatedOrder := 0 for i := range v { left := (i - 1) % len(v) //This is to work around the fact that in Go //modulo of a negative number will not return a positive number. //So -1 % 4 will not return 3 but -1. In that case we add length. if left < 0 { left += len(v) } right := (i + 1) % len(v) // fmt.Printf("Left: %d; Right: %d\n", left, right) leftLike := getLikeForTargetConnect(v[i], v[left]) rightLike := getLikeForTargetConnect(v[i], v[right]) // fmt.Printf("Name: %s; Left:%d; Right:%d\n", v[i], leftLike, rightLike) calculatedOrder += leftLike + rightLike } // fmt.Printf("Order for: %v; Calc:%d\n", v, calculatedOrder) if calculatedOrder > bestSeating { bestSeating = calculatedOrder } } return bestSeating } func getLikeForTargetConnect(name string, neighbour string) int { neighbours := table[name] for _, t := range neighbours { if v, ok := t[neighbour]; ok { return v } } return 0 } This is quiet large. And takes a bit of explaining. So what is happening here? We are putting the names which correspond with numbers and neighbours into a map which has a map as a value. The map contains seating information for a person. For example, next to Alice, a bunch of people can sit, and they have a certain relationship to Alice, represented by a number. ...