feat(js): add modular solution and documentation for hard challenge 1 - Travelling Salesman Problem (Bitmasking)

Author: IbatoLionDev

3-HARD/JavaScript/1-travelling-salesman-bitmasking/README.md

@@ -0,0 +1,80 @@
+# Travelling Salesman Problem - Bitmasking Approach
+
+## English
+
+The Travelling Salesman Problem (TSP) is a classic algorithmic problem in the field of computer science and operations research. It focuses on optimization. In this problem, a salesman is given a list of cities and must determine the shortest possible route that visits each city exactly once and returns to the origin city.
+
+This challenge requires implementing the TSP using bitmasking and dynamic programming to efficiently explore all possible routes without redundant calculations. The solution is implemented in JavaScript using Object-Oriented Programming (OOP) principles and follows DRY (Don't Repeat Yourself) best practices.
+
+### Relevant Code Snippet
+
+```javascript
+class TravellingSalesman {
+  constructor(distanceMatrix) {
+    this.distanceMatrix = distanceMatrix;
+    this.n = distanceMatrix.length;
+    this.memo = Array.from({ length: this.n }, () => []);
+  }
+
+  tsp(mask = 1, pos = 0) {
+    if (mask === (1 << this.n) - 1) {
+      return this.distanceMatrix[pos][0];
+    }
+    if (this.memo[pos][mask] !== undefined) {
+      return this.memo[pos][mask];
+    }
+
+    let minCost = Infinity;
+    for (let city = 0; city < this.n; city++) {
+      if ((mask & (1 << city)) === 0) {
+        const newCost = this.distanceMatrix[pos][city] + this.tsp(mask | (1 << city), city);
+        if (newCost < minCost) {
+          minCost = newCost;
+        }
+      }
+    }
+    this.memo[pos][mask] = minCost;
+    return minCost;
+  }
+}
+```
+
+---
+
+## Español
+
+El Problema del Viajante de Comercio (TSP) es un problema clásico en el campo de la informática y la investigación operativa. Se centra en la optimización. En este problema, un viajante debe determinar la ruta más corta posible que visite cada ciudad exactamente una vez y regrese a la ciudad de origen.
+
+Este reto requiere implementar el TSP usando bitmasking y programación dinámica para explorar eficientemente todas las rutas posibles sin cálculos redundantes. La solución está implementada en JavaScript usando principios de Programación Orientada a Objetos (POO) y siguiendo las mejores prácticas de DRY (No te repitas).
+
+### Fragmento de Código Relevante
+
+```javascript
+class TravellingSalesman {
+  constructor(distanceMatrix) {
+    this.distanceMatrix = distanceMatrix;
+    this.n = distanceMatrix.length;
+    this.memo = Array.from({ length: this.n }, () => []);
+  }
+
+  tsp(mask = 1, pos = 0) {
+    if (mask === (1 << this.n) - 1) {
+      return this.distanceMatrix[pos][0];
+    }
+    if (this.memo[pos][mask] !== undefined) {
+      return this.memo[pos][mask];
+    }
+
+    let minCost = Infinity;
+    for (let city = 0; city < this.n; city++) {
+      if ((mask & (1 << city)) === 0) {
+        const newCost = this.distanceMatrix[pos][city] + this.tsp(mask | (1 << city), city);
+        if (newCost < minCost) {
+          minCost = newCost;
+        }
+      }
+    }
+    this.memo[pos][mask] = minCost;
+    return minCost;
+  }
+}

3-HARD/JavaScript/1-travelling-salesman-bitmasking/proposed-solution/TravellingSalesman.js

@@ -0,0 +1,33 @@
+// TravellingSalesman.js - TSP solver using Bitmasking and Dynamic Programming with OOP and DRY principles
+
+class TravellingSalesman {
+  constructor(distanceMatrix) {
+    this.distanceMatrix = distanceMatrix;
+    this.n = distanceMatrix.length;
+    this.memo = Array.from({ length: this.n }, () => []);
+  }
+
+  tsp(mask = 1, pos = 0) {
+    if (mask === (1 << this.n) - 1) {
+      return this.distanceMatrix[pos][0];
+    }
+    if (this.memo[pos][mask] !== undefined) {
+      return this.memo[pos][mask];
+    }
+
+    let minCost = Infinity;
+    for (let city = 0; city < this.n; city++) {
+      if ((mask & (1 << city)) === 0) {
+        const newCost =
+          this.distanceMatrix[pos][city] + this.tsp(mask | (1 << city), city);
+        if (newCost < minCost) {
+          minCost = newCost;
+        }
+      }
+    }
+    this.memo[pos][mask] = minCost;
+    return minCost;
+  }
+}
+
+export default TravellingSalesman;

3-HARD/JavaScript/1-travelling-salesman-bitmasking/proposed-solution/main.js

@@ -0,0 +1,22 @@
+/*
+Challenge:  
+Given a set of cities and the distances between every pair of cities, find the shortest possible route that visits each city exactly once and returns to the origin city.  
+This challenge requires implementing the Travelling Salesman Problem (TSP) using bitmasking and dynamic programming to optimize the solution.
+*/
+
+import TravellingSalesman from "./TravellingSalesman.js";
+
+function main() {
+  const distanceMatrix = [
+    [0, 10, 15, 20],
+    [10, 0, 35, 25],
+    [15, 35, 0, 30],
+    [20, 25, 30, 0],
+  ];
+
+  const tspSolver = new TravellingSalesman(distanceMatrix);
+  const minCost = tspSolver.tsp();
+  console.log("Minimum cost to visit all cities:", minCost);
+}
+
+main();

README.md

@@ -40,7 +40,7 @@ To maintain an organized and scalable project, we suggest the following folder s
 
 The `proposed-solution` folder is exclusive for the solution by the owner @IbatoLionDev. To add your own solutions, please create a folder with your GitHub handle (e.g., `@YourUsername`) at the same level as the `proposed-solution` folder, not inside it. Place your code inside your folder.
 
-If you, as an independent user, feel the need to explain your solution, please prepare an `article.md` file inside your folder.
+If you, as an independent user, feel the need to explain your solution, please prepare an `README.md` file inside your folder.
 
 ---
 
@@ -84,4 +84,4 @@ Para mantener un proyecto organizado y escalable, sugerimos la siguiente estruct
 
 La carpeta `propuesta-solucion` es exclusiva para la solución del propietario @IbatoLionDev. Para añadir tus propias soluciones, crea una carpeta con tu usuario de GitHub (por ejemplo, `@TuUsuario`) al mismo nivel que la carpeta `propuesta-solucion`, no dentro de ella. Coloca tu código dentro de tu carpeta.
 
-Si tú, como usuario independiente, consideras necesario explicar tu solución, por favor prepara un archivo `articulo.md` dentro de tu carpeta.
+Si tú, como usuario independiente, consideras necesario explicar tu solución, por favor prepara un archivo `README.md` dentro de tu carpeta.