From 14f93c7c91240b154817a92149ed354d0723eec5 Mon Sep 17 00:00:00 2001
From: Everton Braga <evertonr.braga@gmail.com>
Date: Wed, 28 Oct 2020 21:06:52 -0300
Subject: [PATCH] JS graphs

---
 JavaScript/Graphs/index.js | 161 +++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 JavaScript/Graphs/index.js

diff --git a/JavaScript/Graphs/index.js b/JavaScript/Graphs/index.js
new file mode 100644
index 00000000..51b59920
--- /dev/null
+++ b/JavaScript/Graphs/index.js
@@ -0,0 +1,161 @@
+function Dictionary() {
+  var items = {};
+
+  this.set = function (key, value) {
+    items[key] = value;
+  };
+
+  this.delete = function (key) {
+    if (this.has(key)) {
+      delete items[key];
+      return true;
+    }
+    return false;
+  };
+
+  this.has = function (key) {
+    return items.hasOwnProperty(key);
+  };
+
+  this.get = function (key) {
+    return this.has(key) ? items[key] : undefined;
+  };
+
+  this.clear = function () {
+    items = {};
+  };
+
+  this.size = function () {
+    return Object.keys(items).length;
+  };
+
+  this.keys = function () {
+    return Object.keys(items);
+  };
+
+  this.values = function () {
+    var values = [],
+      keys = Object.keys(items);
+
+    for (var i = 0; i < keys.length; i++) {
+      values.push(items[keys[i]]);
+    }
+    return values;
+  };
+
+  this.getItems = function () {
+    return items;
+  };
+}
+
+function Queue() {
+  var items = [];
+
+  this.enqueue = function (element) {
+    items.push(element);
+  };
+
+  this.dequeue = function () {
+    return items.shift();
+  };
+
+  this.front = function () {
+    return items[0];
+  };
+
+  this.isEmpty = function () {
+    return items.length === 0;
+  };
+
+  this.size = function () {
+    return items.length;
+  };
+
+  this.print = function () {
+    console.log(items.toString());
+  };
+}
+
+function Graph() {
+  var vertices = [];
+  var adjList = new Dictionary();
+
+  this.addVertex = function (v) {
+    vertices.push(v);
+    adjList.set(v, []);
+  };
+
+  this.addEdge = function (v, w) {
+    adjList.get(v).push(w);
+    adjList.get(w).push(v);
+  };
+
+  this.toString = function () {
+    var s = '';
+    for (var i = 0; i < vertices.length; i++) {
+      s += vertices[i] + ' -> ';
+      var neighbors = adjList.get(vertices[i]);
+      for (var j = 0; j < neighbors.length; j++) {
+        s += neighbors[j] + ' ';
+      }
+      s += '\n';
+    }
+    return s;
+  };
+
+  var initializeColor = function () {
+    var color = [];
+    for (var i = 0; i < vertices.length; i++) {
+      color[vertices[i]] = 'white';
+    }
+    return color;
+  };
+
+  this.bfs = function (v, callback) {
+    var color = initializeColor(),
+      queue = new Queue();
+    queue.enqueue(v);
+
+    while (!queue.isEmpty()) {
+      var u = queue.dequeue(),
+        neighbors = adjList.get(u);
+      color[u] = 'grey';
+      for (var i = 0; i < neighbors.length; i++) {
+        var w = neighbors[i];
+        if (color[w] === 'white') {
+          color[w] = 'grey';
+          queue.enqueue(w);
+        }
+      }
+      color[u] = 'black';
+      callback(u);
+    }
+  };
+
+  this.dfs = function (callback) {
+    var color = initializeColor();
+    for (var i = 0; i < vertices.length; i++) {
+      if (color[vertices[i]] === 'white') {
+        dfsVisit(vertices[i], color, callback);
+      }
+    }
+  };
+
+  var dfsVisit = function (u, color, callback) {
+    color[u] = 'grey';
+    callback(u);
+
+    var neighbors = adjList.get(u);
+    for (var i = 0; i < neighbors.length; i++) {
+      var w = neighbors[i];
+      if (color[w] === 'white') {
+        dfsVisit(w, color, callback);
+      }
+    }
+    color[u] = 'black';
+  };
+}
+
+function printNode(value) {
+  console.log('Visited vertex: ' + value);
+}