Merge pull request neetcode-gh#172 from jktam336/jktam336/684-Redundant-Connection

Added JS 684-Redundant-Connection

Author: neetcode-gh

javascript/684-Redundant-Connection.js

@@ -0,0 +1,39 @@
+/**
+ * @param {number[][]} edges
+ * @return {number[]}
+ */
+ var findRedundantConnection = function(edges) {
+	const parents = [];
+	const rank = new Array(edges.length).fill(1);
+	for (let i = 0; i < edges.length; i++) {
+		parents[i] = i;
+	};
+
+  function find(n) {
+    let parent = parents[n];
+    while (parent !== parents[parent]) {
+			parents[parent] = parents[parents[parent]];
+      parent = parents[parent];
+    }
+    return parent;
+  }
+
+	function join(vertex1, vertex2) {
+		const parent1 = find(vertex1);
+		const parent2 = find(vertex2);
+		if (parent1 == parent2) return false;
+		
+		if (rank[parent1] > rank[parent2]) {
+			parents[parent2] = parent1;
+      rank[parent1] += rank[parent2];
+		} else {
+      parents[parent1] = parent2;
+      rank[parent2] += rank[parent1];
+		};
+		return true;
+	};
+
+	for (const edge of edges) {
+		if (!join(edge[0]-1, edge[1]-1)) return edge;
+	};
+};