# Clone Graph LeetCode Solution

Here, We see Clone Graph LeetCode Solution. This Leetcode problem is done in many programming languages like C++, Java, JavaScript, Python, etc. with different approaches.

# List of all LeetCode Solution

## Problem Statement

Given a reference of a node in a connected undirected graph.

Return a deep copy (clone) of the graph.

Each node in the graph contains a value (`int`) and a list (`List[Node]`) of its neighbors.class Node { public int val; public List<Node> neighbors; }

Test case format:

For simplicity, each node’s value is the same as the node’s index (1-indexed). For example, the first node with `val == 1`, the second node with `val == 2`, and so on. The graph is represented in the test case using an adjacency list.

An adjacency list is a collection of unordered lists used to represent a finite graph. Each list describes the set of neighbors of a node in the graph.

The given node will always be the first node with `val = 1`. You must return the copy of the given node as a reference to the cloned graph.

Example 1:

Output: [[2,4],[1,3],[2,4],[1,3]]
Explanation:
There are 4 nodes in the graph.
1st node (val = 1)’s neighbors are 2nd node (val = 2) and 4th node (val = 4).
2nd node (val = 2)’s neighbors are 1st node (val = 1) and 3rd node (val = 3).
3rd node (val = 3)’s neighbors are 2nd node (val = 2) and 4th node (val = 4).
4th node (val = 4)’s neighbors are 1st node (val = 1) and 3rd node (val = 3).

Example 2:

Output: [[]]
Explanation: Note that the input contains one empty list. The graph consists of only one node with val = 1 and it does not have any neighbors.

Example 3:
Output: []
Explanation: This an empty graph, it does not have any nodes.

## Clone Graph LeetCode SolutionC++

``````class Solution {
public:
Node* dfs(Node* cur,unordered_map<Node*,Node*>& mp)
{
vector<Node*> neighbour;
Node* clone=new Node(cur->val);
mp[cur]=clone;
for(auto it:cur->neighbors)
{
if(mp.find(it)!=mp.end())
{
neighbour.push_back(mp[it]);
}
else
neighbour.push_back(dfs(it,mp));
}
clone->neighbors=neighbour;
return clone;
}
Node* cloneGraph(Node* node) {
unordered_map<Node*,Node*> mp;
if(node==NULL)
return NULL;
if(node->neighbors.size()==0)
{
Node* clone= new Node(node->val);
return clone;
}
return dfs(node,mp);
}
};```Code language: PHP (php)```

## Clone Graph LeetCode SolutionJava

``````class Solution {
public Node cloneGraph(Node node) {
if (node == null) {
return null;
}
Map<Node, Node> visited = new HashMap<>();
return cloneGraphHelper(node, visited);
}

private Node cloneGraphHelper(Node node, Map<Node, Node> visited) {
Node copy = new Node(node.val);
visited.put(node, copy);
for (Node neighbor : node.neighbors) {
if (visited.containsKey(neighbor)) {
} else {
Node neighborCopy = cloneGraphHelper(neighbor, visited);
}
}
return copy;
}
}```Code language: JavaScript (javascript)```

## Clone Graph LeetCode SolutionJavaScript

``````var cloneGraph = function(node) {
let start = node;
if (start === null) return null;
const vertexMap = new Map();
const queue = [start]
vertexMap.set(start, new Node(start.val));
while (queue.length > 0) {
const currentVertex = queue.shift();
for (const neighbor of currentVertex.neighbors) {
if (!vertexMap.has(neighbor)) {
vertexMap.set(neighbor, new Node(neighbor.val))
queue.push(neighbor);
}
vertexMap.get(currentVertex).neighbors.push(vertexMap.get(neighbor));
}
}
return vertexMap.get(start);
};```Code language: JavaScript (javascript)```

## Clone Graph SolutionPython

``````class Solution(object):
def cloneGraph(self, node):
if not node:
return None
cloned = {}
stack = [node]
cloned[node] = Node(node.val)
while stack:
curr = stack.pop()
for neighbor in curr.neighbors:
if neighbor not in cloned:
cloned[neighbor] = Node(neighbor.val)
stack.append(neighbor)
cloned[curr].neighbors.append(cloned[neighbor])
return cloned[node]``````
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