Merge pull request neetcode-gh#1064 from notauserx/684-Redundant-Conn…

…ection.cs

Create 684-Redundant-Connection.cs

csharp/684-Redundant-Connection.cs

@@ -0,0 +1,45 @@
+public class Solution {
+ public int[] FindRedundantConnection(int[][] edges) {
+ var nodes = edges.Length;
+ int[] parent = new int[nodes + 1];
+ int[] rank = new int[nodes + 1];
+
+ for(int i = 0; i < nodes; i++) {
+ parent[i] = i;
+ rank[i] = 1;
+ }
+
+ int findParent (int n) {
+ var p = parent[n];
+
+ while(p != parent[p]) {
+ parent[p] = parent[parent[p]];
+ p = parent[p];
+ }
+
+ return p;
+ }
+ bool union(int n1, int n2) {
+ (int p1, int p2) = (findParent(n1), findParent(n2));
+
+ if(p1 == p2) return false;
+
+ if(rank[p1] > rank[p2]) {
+ parent[p2] = p1;
+ rank[p1] += rank[p2];
+ } else {
+ parent[p1] = p2;
+ rank[p2] += rank[p1];
+ }
+
+ return true;
+ }
+
+ foreach(var edge in edges) {
+ if(union(edge[0], edge[1]) is false) 
+ return edge;
+ }
+
+ return new int[2];
+ }
+}