diff --git a/leetcode/133. Clone Graph/README.md b/leetcode/133. Clone Graph/README.md index 7e477517..27eb0c2f 100644 --- a/leetcode/133. Clone Graph/README.md +++ b/leetcode/133. Clone Graph/README.md @@ -1,10 +1,10 @@ # [133. Clone Graph (Medium)](https://leetcode.com/problems/clone-graph/) -

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

+

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 val (int) and a list (List[Node]) of its neighbors.

+

Each node in the graph contains a value (int) and a list (List[Node]) of its neighbors.

class Node {
     public int val;
@@ -16,15 +16,15 @@
 
 
Test case format:

 
-
For simplicity sake, 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.

+
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.

 
-
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.

+
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.

+
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:

-
+
 
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.
@@ -48,26 +48,23 @@
 Explanation: This an empty graph, it does not have any nodes.
 

 
-
Example 4:

-
-
Input: adjList = [[2],[1]]
-Output: [[2],[1]]
-

-
 
 

 
Constraints:

 
 
 
 
+**Companies**:  
+[Facebook](https://leetcode.com/company/facebook), [Amazon](https://leetcode.com/company/amazon), [Microsoft](https://leetcode.com/company/microsoft), [Google](https://leetcode.com/company/google), [Bloomberg](https://leetcode.com/company/bloomberg), [Salesforce](https://leetcode.com/company/salesforce), [Twitter](https://leetcode.com/company/twitter), [Oracle](https://leetcode.com/company/oracle)
+
 **Related Topics**:  
-[Depth-first Search](https://leetcode.com/tag/depth-first-search/), [Breadth-first Search](https://leetcode.com/tag/breadth-first-search/), [Graph](https://leetcode.com/tag/graph/)
+[Hash Table](https://leetcode.com/tag/hash-table/), [Depth-First Search](https://leetcode.com/tag/depth-first-search/), [Breadth-First Search](https://leetcode.com/tag/breadth-first-search/), [Graph](https://leetcode.com/tag/graph/)
 
 **Similar Questions**:
 * [Copy List with Random Pointer (Medium)](https://leetcode.com/problems/copy-list-with-random-pointer/)
@@ -87,13 +84,12 @@ class Solution {
     unordered_map m;
 public:
     Node* cloneGraph(Node* node) {
-        if (!node) return NULL;
-        if (m.count(node) == 0) {
-            auto copy = new Node(node->val);
-            m[node] = copy;
-            for (auto nei : node->neighbors) copy->neighbors.push_back(cloneGraph(nei));
-        }
-        return m[node];
+        if (!node) return nullptr;
+        if (m.count(node)) return m[node];
+        auto cpy = new Node(node->val);
+        m[node] = cpy;
+        for (auto &n : node->neighbors) cpy->neighbors.push_back(cloneGraph(n));
+        return cpy;
     }
 };
 ```
@@ -109,7 +105,7 @@ public:
 class Solution {
 public:
     Node* cloneGraph(Node* node) {
-        if (!node) return NULL;
+        if (!node) return nullptr;
         queue q;
         unordered_map m;
         m[node] = new Node(node->val);