Search Graph Nodes

Given a undirected graph, a node and a target, return the nearest node to given node which value of it is target, return NULL if you can’t find.

There is a mapping store the nodes’ values in the given parameters.

Notice

It’s guaranteed there is only one available solution

Have you met this question in a real interview? Yes
Example
2——3 5
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1 –4
Give a node 1, target is 50

there a hash named values which is [3,4,10,50,50], represent:
Value of node 1 is 3
Value of node 2 is 4
Value of node 3 is 10
Value of node 4 is 50
Value of node 5 is 50

Return node 4

这道题目基本上就是一个变形后的BFS，因此并不困难
java

/** * Definition for graph node. * class UndirectedGraphNode { *     int label; *     ArrayList<UndirectedGraphNode> neighbors; *     UndirectedGraphNode(int x) {  *         label = x; neighbors = new ArrayList<UndirectedGraphNode>();  *     } * }; */public class Solution {    /*     * @param graph: a list of Undirected graph node     * @param values: a hash mapping, <UndirectedGraphNode, (int)value>     * @param node: an Undirected graph node     * @param target: An integer     * @return: a node     */    public UndirectedGraphNode searchNode(ArrayList<UndirectedGraphNode> graph,                                          Map<UndirectedGraphNode, Integer> values,                                          UndirectedGraphNode node,                                          int target) {        // write your code here        if (node == null) {            return null;        }        Queue<UndirectedGraphNode> queue = new LinkedList<>();        queue.offer(node);        while (!queue.isEmpty()) {            UndirectedGraphNode root = queue.poll();            if (values.get(root) == target) {                return root;            }            for (UndirectedGraphNode val : root.neighbors) {                queue.offer(val);            }        }        return null;    }}

python

"""Definition for a undirected graph nodeclass UndirectedGraphNode:    def __init__(self, x):        self.label = x        self.neighbors = []"""import Queueclass Solution:    """    @param: graph: a list of Undirected graph node    @param: values: a hash mapping, <UndirectedGraphNode, (int)value>    @param: node: an Undirected graph node    @param: target: An integer    @return: a node    """    def searchNode(self, graph, values, node, target):        # write your code here        if node is None:            return None        queue = Queue.Queue()        queue.put(node)        while not queue.empty():            root = queue.get()            if values[root] == target:                return root            for ele in root.neighbors:                queue.put(ele)        return None