cpp-flashcards/org/study_deck_02/dsa/graphs/0133-clone-graph.org

#+ANKI_DECK: study_deck_02
* TODO 0133. Clone Graph :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0133. Clone Graph][0133. Clone Graph]]
:END:

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.


#+begin_src
class Node {
    public int val;
    public List<Node> neighbors;
}
#+end_src


*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:*


#+begin_src
Input: adjList = [[2,4],[1,3],[2,4],[1,3]]
Output: [[2,4],[1,3],[2,4],[1,3]]
Explanation: There are 4 nodes in the graph.
1st node (val = 1)&#39;s neighbors are 2nd node (val = 2) and 4th node (val = 4).
2nd node (val = 2)&#39;s neighbors are 1st node (val = 1) and 3rd node (val = 3).
3rd node (val = 3)&#39;s neighbors are 2nd node (val = 2) and 4th node (val = 4).
4th node (val = 4)&#39;s neighbors are 1st node (val = 1) and 3rd node (val = 3).
#+end_src


*Example 2:*


#+begin_src
Input: adjList = [[]]
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.
#+end_src


*Example 3:*


#+begin_src
Input: adjList = []
Output: []
Explanation: This an empty graph, it does not have any nodes.
#+end_src


*Constraints:*

 - The number of nodes in the graph is in the range ~[0, 100]~.

 - ~1 <= Node.val <= 100~

 - ~Node.val~ is unique for each node.

 - There are no repeated edges and no self-loops in the graph.

 - The Graph is connected and all nodes can be visited starting from the given node.

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
"""
# Definition for a Node.
class Node:
    def __init__(self, val = 0, neighbors = None):
        self.val = val
        self.neighbors = neighbors if neighbors is not None else []
"""

from typing import Optional
class Solution:
    def cloneGraph(self, node: Optional['Node']) -> Optional['Node']:
#+end_src

** TODO C++
#+begin_src cpp
/*
// Definition for a Node.
class Node {
public:
    int val;
    vector<Node*> neighbors;
    Node() {
        val = 0;
        neighbors = vector<Node*>();
    }
    Node(int _val) {
        val = _val;
        neighbors = vector<Node*>();
    }
    Node(int _val, vector<Node*> _neighbors) {
        val = _val;
        neighbors = _neighbors;
    }
};
*/

class Solution {
public:
    Node* cloneGraph(Node* node) {
        
    }
};
#+end_src