diff --git a/07/index.md b/07/index.md new file mode 100644 index 0000000..506d53e --- /dev/null +++ b/07/index.md @@ -0,0 +1,229 @@ +# 06.11.2023 + +- [06.11.2023](#06112023) + - [Resources](#resources) + - [Try and retry](#try-and-retry) + - [Packing a backpack](#packing-a-backpack) + - [Traveling salesmen](#traveling-salesmen) + - [Shortest path problem](#shortest-path-problem) + +## Resources + +- [Wikipedia - Travelling salesman problem](https://en.wikipedia.org/wiki/Travelling_salesman_problem) +- [Wikipedia - Shortest path problem](https://en.wikipedia.org/wiki/Shortest_path_problem) + +## Try and retry + +### Packing a backpack + +### Traveling salesmen + +### Shortest path problem + +Trying to come up with a solution to find the shortest path to visit a list of friends. Each friend can only be visited once. + +```javascript +const hans = "hans" +const leia = "leia" +const jana = "jana" +const petra = "petra" +const louis = "louis" +const ina = "ina" + +const stops = [ + { + name: hans, + destinations: [ + { + name: ina, + distance: 2 + }, + { + name: leia, + distance: 3 + }, + { + name: jana, + distance: 3 + }, + { + name: petra, + distance: 3 + }, + { + name: louis, + distance: 5 + } + ] + }, + { + name: petra, + destinations: [ + { + name: hans, + distance: 3 + }, + { + name: jana, + distance: 4 + }, + { + name: ina, + distance: 5 + }, + { + name: leia, + distance: 6 + }, + { + name: louis, + distance: 7 + } + ] + }, + { + name: ina, + destinations: [ + { + name: hans, + distance: 2 + }, + { + name: jana, + distance: 2 + }, + { + name: louis, + distance: 3 + }, + { + name: petra, + distance: 5 + }, + { + name: leia, + distance: 8 + } + ] + }, + { + name: jana, + destinations: [ + { + name: leia, + distance: 1 + }, + { + name: louis, + distance: 2 + }, + { + name: ina, + distance: 3 + }, + { + name: hans, + distance: 3 + }, + { + name: petra, + distance: 4 + } + ] + }, + { + name: leia, + destinations: [ + { + name: jana, + distance: 1 + }, + { + name: louis, + distance: 2 + }, + { + name: hans, + distance: 3 + }, + { + name: petra, + distance: 6 + }, + { + name: ina, + distance: 8 + } + ] + }, + { + name: louis, + destinations: [ + { + name: jana, + distance: 2 + }, + { + name: leia, + distance: 2 + }, + { + name: ina, + distance: 3 + }, + { + name: hans, + distance: 5 + }, + { + name: petra, + distance: 7 + } + ] + } +] +const solutions = []; +const maxTries = stops.length * stops.length; +for (let i = 0; i < stops.length; i++) { + let currentTries = 0; + while (currentTries < maxTries) { + let currentSolution = { + stops: [stops[i].name], + distance: 0 + }; + let hasShortestDistance = solutions.length > 0; + let shortestDistance = hasShortestDistance ? solutions.sort((a, b) => { + if (a.distance == b.distance) return 0; + if (a.distance > b.distance) return 1; + return -1; + })[0] : null; + let stopAdded = false; + let isTooLong = false; + while (true) { + stopAdded = false; + for (let destination of stops[i].destinations) { + if (currentSolution.stops.indexOf(destination.name) > -1) { + continue; + } + currentSolution.stops.push(destination.name); + currentSolution.distance += destination.distance; + if (hasShortestDistance && shortestDistance && currentSolution.distance >= shortestDistance.distance) { + isTooLong = true; + } + stopAdded = true; + break; + } + if (!stopAdded || isTooLong) { + break; + } + } + + if (!isTooLong && currentSolution.stops.length == stops.length) { + solutions.push(currentSolution); + } + isTooLong = false; + currentTries++; + } +} +``` +