Merge pull request #3476 from matthewkeck/Create-0127-word-ladder

Create: 0127-word-ladder.dart

Author: Ykhan799

dart/0127-word-ladder.dart

@@ -0,0 +1,48 @@
+class Solution {
+  List<int> findRedundantConnection(List<List<int>> edges) {
+    List<int> parent = [];
+    for (int i = 0; i < edges.length + 1; i++) {
+      parent.add(i);
+    }
+
+    List<int> sizes = List.filled(edges.length + 1, 1);
+
+    int find(int n) {
+      int p = parent[n];
+
+      while (p != parent[p]) {
+        parent[p] = parent[parent[p]];
+        p = parent[p];
+      }
+
+      return p;
+    }
+
+    bool union(int node1, int node2) {
+      int parentOf1 = find(node1);
+      int parentOf2 = find(node2);
+
+      if (parentOf1 == parentOf2) {
+        return false;
+      } else if (sizes[parentOf1] > sizes[parentOf2]) {
+        parent[parentOf2] = parentOf1;
+        sizes[parentOf1] += sizes[parentOf2];
+      } else {
+        parent[parentOf1] = parentOf2;
+        sizes[parentOf2] += sizes[parentOf1];
+      }
+
+      return true;
+    }
+
+    for (List<int> edge in edges) {
+      int node1 = edge[0];
+      int node2 = edge[1];
+      if (!union(node1, node2)) {
+        return [node1, node2];
+      }
+    }
+
+    return [];
+  }
+}