[leetcode] 133 clone graph bfs

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<span style="font-family: Arial, Helvetica, sans-serif; font-size: 12px; background-color: rgb(255, 255, 255);">bfs:</span>

1. 一个HashMap<Node, Node>来找对应的cloned node

2. 一个queue<Node>来装frontier

3. 一边建node一边连接node

/** * Definition for undirected graph. * class UndirectedGraphNode { *     int label; *     List<UndirectedGraphNode> neighbors; *     UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); } * }; * 9:34 */public class Solution {    public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {        if (node==null) return null;        HashMap<UndirectedGraphNode, UndirectedGraphNode> map = new HashMap<UndirectedGraphNode,UndirectedGraphNode>();        Queue<UndirectedGraphNode> frontier = new LinkedList<UndirectedGraphNode>();        UndirectedGraphNode clone = new UndirectedGraphNode(node.label);        map.put(node, clone);        frontier.add(node);        while (!frontier.isEmpty()) {            UndirectedGraphNode cur = frontier.remove();            clone = map.get(cur);            for (UndirectedGraphNode n: cur.neighbors) {                if (map.containsKey(n)) clone.neighbors.add(map.get(n));                else {                    UndirectedGraphNode newNode = new UndirectedGraphNode(n.label);                    map.put(n, newNode);                    clone.neighbors.add(newNode);                    frontier.add(n);                }            }        }        return map.get(node);    }}

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