| 126 | return self.parent[item] |
| 127 | |
| 128 | def union(self, item1, item2): |
| 129 | root1 = self.find(item1) |
| 130 | root2 = self.find(item2) |
| 131 | |
| 132 | if root1 == root2: |
| 133 | return root1 |
| 134 | |
| 135 | if self.rank[root1] > self.rank[root2]: |
| 136 | self.parent[root2] = root1 |
| 137 | return root1 |
| 138 | |
| 139 | if self.rank[root1] < self.rank[root2]: |
| 140 | self.parent[root1] = root2 |
| 141 | return root2 |
| 142 | |
| 143 | if self.rank[root1] == self.rank[root2]: |
| 144 | self.rank[root1] += 1 |
| 145 | self.parent[root2] = root1 |
| 146 | return root1 |
| 147 | return None |
| 148 | |
| 149 | @staticmethod |
| 150 | def boruvka_mst(graph): |