無向グラフノード
class Node {
public int val;
public List<Node> neighbors;
public Node() {
val = 0;
neighbors = new ArrayList<Node>();
}
public Node(int _val) {
val = _val;
neighbors = new ArrayList<Node>();
}
public Node(int _val, ArrayList<Node> _neighbors) {
val = _val;
neighbors = _neighbors;
}
}
方法1、深さ優先走査アルゴリズムのコピー:
class Solution {
private HashMap <Node, Node> visited = new HashMap <> ();
public Node cloneGraph(Node node) {
if (node == null) {
return node;
}
if (visited.containsKey(node)) {
return visited.get(node);
}
Node cloneNode = new Node(node.val, new ArrayList());
visited.put(node, cloneNode);
for (Node neighbor: node.neighbors) {
cloneNode.neighbors.add(cloneGraph(neighbor));
}
return cloneNode;
}
}
方法2:幅優先探索アルゴリズムのコピー:
class Solution {
public Node cloneGraph(Node node) {
if (node == null) {
return node;
}
HashMap<Node, Node> visited = new HashMap();
LinkedList<Node> queue = new LinkedList<Node> ();
queue.add(node);
visited.put(node, new Node(node.val, new ArrayList()));
while (!queue.isEmpty()) {
Node n = queue.remove();
for (Node neighbor: n.neighbors) {
if (!visited.containsKey(neighbor)) {
visited.put(neighbor, new Node(neighbor.val, new ArrayList()));
queue.add(neighbor);
}
visited.get(n).neighbors.add(visited.get(neighbor));
}
}
return visited.get(node);
}
}