Clone Graph

来源：互联网发布：川大网络教育编辑：程序博客网时间：2024/05/22 02:18

updated: 06/10, 我们必须深刻理解什么是clone，不要将引用克隆

curNodeClone.neighbors.add(curNodeNeighborClone);

加入的是clone，而不是现有的引用

典型的bfs遍历问题，基本功

很棒的代码点击打开链接

/**     * @param node: A undirected graph node     * @return: A undirected graph node     */    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {        if (node == null) {            return null;        }        // 放原始node和其复制品          Map<UndirectedGraphNode, UndirectedGraphNode> map = new HashMap<>();        // BFS用的queue        List<UndirectedGraphNode> list = new LinkedList<UndirectedGraphNode>();         // 根节点的复制        UndirectedGraphNode nodeClone = new UndirectedGraphNode(node.label);        // 把根节点和其复制品放入map         map.put(node, nodeClone);        //添加入队列          list.add(node);        while (!list.isEmpty()) {            // 当前处理对象            UndirectedGraphNode curNode = list.remove(0);            // 得到当前原始对象的所有neighbor              ArrayList<UndirectedGraphNode> curNodeNeighbors = curNode.neighbors;            // 当前处理对象的复制品，必定在map里，因为在前面的neighbor里已经被创建            UndirectedGraphNode curNodeClone = map.get(curNode);            for (UndirectedGraphNode curNodeNeighbor: curNodeNeighbors) {                if (map.containsKey(curNodeNeighbor)) {                    //UndirectedGraphNode curNodeClone = map.get(curNode);                    // 之前已经被复制过的neighbor                    UndirectedGraphNode curNodeNeighborClone = map.get(curNodeNeighbor);                    // 就直接从map里取出neighborClone, 给curClone添加复制的neighbor                    curNodeClone.neighbors.add(curNodeNeighborClone);                } else {                    // 如果该neighbor没有被复制过，则新建neighborClone                    UndirectedGraphNode curNodeNeighborClone = new UndirectedGraphNode(curNodeNeighbor.label);                    //UndirectedGraphNode curNodeClone = map.get(curNode);                    curNodeClone.neighbors.add(curNodeNeighborClone);                    // 并且添加到队列里为了将来的遍历                    list.add(curNodeNeighbor);                    // 存储到map里                    map.put(curNodeNeighbor, curNodeNeighborClone);                }            }        }        return nodeClone;    }

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