[LintCode] 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.
It's guaranteed there is only one available solution.
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
1 /** 2 * Definition for graph node. 3 * class UndirectedGraphNode { 4 * int label; 5 * ArrayList<UndirectedGraphNode> neighbors; 6 * UndirectedGraphNode(int x) { 7 * label = x; neighbors = new ArrayList<UndirectedGraphNode>(); 8 * } 9 * }; 10 */ 11 public class Solution { 12 /** 13 * @param graph a list of Undirected graph node 14 * @param values a hash mapping, <UndirectedGraphNode, (int)value> 15 * @param node an Undirected graph node 16 * @param target an integer 17 * @return the a node 18 */ 19 public UndirectedGraphNode searchNode(ArrayList<UndirectedGraphNode> graph, 20 Map<UndirectedGraphNode, Integer> values, 21 UndirectedGraphNode node, 22 int target) { 23 if(graph == null || graph.size() == 0 || node == null) 24 { 25 return null; 26 } 27 if(values.get(node) == target) 28 { 29 return node; 30 } 31 32 Queue<UndirectedGraphNode> queue = new LinkedList<UndirectedGraphNode>(); 33 HashSet<UndirectedGraphNode> visited = new HashSet<UndirectedGraphNode>(); 34 queue.offer(node); 35 visited.add(node); 36 37 while(!queue.isEmpty()) 38 { 39 UndirectedGraphNode headNode = queue.poll(); 40 for(UndirectedGraphNode neighbor : headNode.neighbors) 41 { 42 if(visited.contains(neighbor)) 43 { 44 continue; 45 } 46 if(values.get(neighbor) == target) 47 { 48 return neighbor; 49 } 50 queue.offer(neighbor); 51 visited.add(neighbor); 52 } 53 } 54 return null; 55 } 56 }
Related Problems
Knight Shortest Path
Binary Tree Level Order Traversal II
