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LeetCode-Clone Graph
Clone an undirected graph. Each node in the graph contains a label and a list of its neighbors.
OJ‘s undirected graph serialization:
Nodes are labeled uniquely.
We use # as a separator for each node, and , as a separator for node label and each neighbor of the node.
As an example, consider the serialized graph {0,1,2#1,2#2,2}.
The graph has a total of three nodes, and therefore contains three parts as separated by #.
- First node is labeled as
0. Connect node0to both nodes1and2. - Second node is labeled as
1. Connect node1to node2. - Third node is labeled as
2. Connect node2to node2(itself), thus forming a self-cycle.
Visually, the graph looks like the following:
1 / / 0 --- 2 / \_/
Solution:
1 /** 2 * Definition for undirected graph. 3 * class UndirectedGraphNode { 4 * int label; 5 * List<UndirectedGraphNode> neighbors; 6 * UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); } 7 * }; 8 */ 9 public class Solution {10 public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {11 if (node==null) return null;12 13 Map<UndirectedGraphNode,UndirectedGraphNode> cloneMap = new HashMap<UndirectedGraphNode,UndirectedGraphNode>();14 Set<UndirectedGraphNode> visited = new HashSet<UndirectedGraphNode>();15 cloneMap.put(node, new UndirectedGraphNode(node.label)); 16 17 return cloneGraphRecur(node,cloneMap,visited);18 }19 20 public UndirectedGraphNode cloneGraphRecur(UndirectedGraphNode cur, Map<UndirectedGraphNode,UndirectedGraphNode> cloneMap, Set<UndirectedGraphNode> visited){21 UndirectedGraphNode curClone = cloneMap.get(cur);22 visited.add(cur);23 24 //Clone all the neighbors of cur node.25 for (int i=0;i<cur.neighbors.size();i++){26 UndirectedGraphNode neigh = cur.neighbors.get(i);27 if (cloneMap.containsKey(neigh)){28 curClone.neighbors.add(cloneMap.get(neigh));29 } else {30 UndirectedGraphNode neighClone = new UndirectedGraphNode(neigh.label);31 cloneMap.put(neigh,neighClone);32 curClone.neighbors.add(neighClone);33 }34 }35 36 //Visit all unvisited neighbors of cur node.37 for (int i=0;i<cur.neighbors.size();i++)38 if (!visited.contains(cur.neighbors.get(i)))39 cloneGraphRecur(cur.neighbors.get(i),cloneMap,visited);40 41 return curClone;42 }43 44 }
Solution (BFS):
1 /** 2 * Definition for undirected graph. 3 * class UndirectedGraphNode { 4 * int label; 5 * List<UndirectedGraphNode> neighbors; 6 * UndirectedGraphNode(int x) { label = x; neighbors = new ArrayList<UndirectedGraphNode>(); } 7 * }; 8 */ 9 public class Solution {10 public UndirectedGraphNode cloneGraph(UndirectedGraphNode node) {11 if (node==null) return null;12 13 Map<UndirectedGraphNode,UndirectedGraphNode> cloneMap = new HashMap<UndirectedGraphNode,UndirectedGraphNode>();14 List<UndirectedGraphNode> visited = new ArrayList<UndirectedGraphNode>();15 cloneMap.put(node, new UndirectedGraphNode(node.label)); 16 visited.add(node);17 int index = 0;18 while (index<visited.size()){19 UndirectedGraphNode cur = visited.get(index);20 UndirectedGraphNode curClone = cloneMap.get(cur);21 22 //Clone all the neighbors of cur node.23 for (int i=0;i<cur.neighbors.size();i++){24 UndirectedGraphNode neigh = cur.neighbors.get(i);25 if (cloneMap.containsKey(neigh)){26 curClone.neighbors.add(cloneMap.get(neigh));27 } else {28 UndirectedGraphNode neighClone = new UndirectedGraphNode(neigh.label);29 cloneMap.put(neigh,neighClone);30 curClone.neighbors.add(neighClone);31 visited.add(neigh);32 }33 }34 35 index++;36 }37 38 return cloneMap.get(node);39 40 41 } 42 }
LeetCode-Clone Graph
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