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feat: add solutions to lc problem: No.0133 (#4162)
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‎solution/0100-0199/0133.Clone Graph/README.md

+161-93
Original file line numberDiff line numberDiff line change
@@ -92,7 +92,20 @@ class Node {
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<!-- solution:start -->
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### 方法一
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### 方法一：哈希表 + DFS
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我们用一个哈希表 $\textit{g}$ 记录原图中的每个节点和它的拷贝节点之间的对应关系，然后进行深度优先搜索。
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我们定义函数 $\text{dfs}(node)$，它的功能是返回 $\textit{node}$ 节点的拷贝节点。$\text{dfs}(node)$ 的过程如下：
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- 如果 $\textit{node}$ 是 $\text{null}$，那么 $\text{dfs}(node)$ 的返回值是 $\text{null}$。
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- 如果 $\textit{node}$ 在 $\textit{g}$ 中，那么 $\text{dfs}(node)$ 的返回值是 $\textit{g}[node]$。
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- 否则我们创建一个新的节点 $\textit{cloned}$，并将 $\textit{g}[node]$ 的值设为 $\textit{cloned}$，然后遍历 $\textit{node}$ 的所有邻居节点 $\textit{nxt}$，并将 $\textit{cloned}$ 的邻居节点列表中加入 $\text{dfs}(nxt)$。
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- 最后返回 $\textit{cloned}$。
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在主函数中，我们返回 $\text{dfs}(node)$。
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时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 是节点的数量。
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<!-- tabs:start -->
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@@ -107,23 +120,24 @@ class Node:
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self.neighbors = neighbors if neighbors is not None else []
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"""
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from typing import Optional
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class Solution:
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def cloneGraph(self, node: 'Node') -> 'Node':
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visited = defaultdict()
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def clone(node):
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class Solution:
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def cloneGraph(self, node: Optional["Node"]) -> Optional["Node"]:
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def dfs(node):
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if node is None:
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return None
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if node in visited:
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return visited[node]
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c = Node(node.val)
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visited[node] = c
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for e in node.neighbors:
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c.neighbors.append(clone(e))
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return c
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return clone(node)
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if node in g:
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return g[node]
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cloned = Node(node.val)
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g[node] = cloned
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for nxt in node.neighbors:
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cloned.neighbors.append(dfs(nxt))
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return cloned
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g = defaultdict()
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return dfs(node)
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```
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#### Java
@@ -150,21 +164,25 @@ class Node {
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*/
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class Solution {
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private Map<Node, Node> visited = new HashMap<>();
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private Map<Node, Node> g = new HashMap<>();
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public Node cloneGraph(Node node) {
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return dfs(node);
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}
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private Node dfs(Node node) {
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if (node == null) {
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return null;
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}
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if (visited.containsKey(node)) {
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return visited.get(node);
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}
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Node clone = new Node(node.val);
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visited.put(node, clone);
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for (Node e : node.neighbors) {
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clone.neighbors.add(cloneGraph(e));
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Node cloned = g.get(node);
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if (cloned == null) {
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cloned = new Node(node.val);
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g.put(node, cloned);
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for (Node nxt : node.neighbors) {
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cloned.neighbors.add(dfs(nxt));
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}
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}
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return clone;
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return cloned;
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}
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}
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```
@@ -195,16 +213,23 @@ public:
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class Solution {
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public:
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unordered_map<Node*, Node*> visited;
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Node* cloneGraph(Node* node) {
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if (!node) return nullptr;
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if (visited.count(node)) return visited[node];
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Node* clone = new Node(node->val);
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visited[node] = clone;
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for (auto& e : node->neighbors)
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clone->neighbors.push_back(cloneGraph(e));
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return clone;
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unordered_map<Node*, Node*> g;
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auto dfs = [&](this auto&& dfs, Node* node) -> Node* {
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if (!node) {
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return nullptr;
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}
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if (g.contains(node)) {
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return g[node];
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}
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Node* cloned = new Node(node->val);
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g[node] = cloned;
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for (auto& nxt : node->neighbors) {
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cloned->neighbors.push_back(dfs(nxt));
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}
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return cloned;
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};
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return dfs(node);
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}
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};
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```
@@ -221,99 +246,142 @@ public:
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*/
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func cloneGraph(node *Node) *Node {
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visited := map[*Node]*Node{}
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var clone func(node *Node) *Node
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clone = func(node *Node) *Node {
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g := map[*Node]*Node{}
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var dfs func(node *Node) *Node
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dfs = func(node *Node) *Node {
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if node == nil {
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return nil
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}
230-
if _, ok := visited[node]; ok {
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return visited[node]
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if n, ok := g[node]; ok {
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return n
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}
233-
c := &Node{node.Val, []*Node{}}
234-
visited[node] = c
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for _, e := range node.Neighbors {
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c.Neighbors = append(c.Neighbors, clone(e))
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cloned := &Node{node.Val, []*Node{}}
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g[node] = cloned
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for _, nxt := range node.Neighbors {
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cloned.Neighbors = append(cloned.Neighbors, dfs(nxt))
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}
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return c
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return cloned
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}
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return clone(node)
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return dfs(node)
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}
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```
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#### TypeScript
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```ts
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/**
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* Definition for Node.
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* class Node {
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* Definition for _Node.
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* class _Node {
251275
* val: number
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* neighbors: Node[]
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* constructor(val?: number, neighbors?: Node[]) {
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* neighbors: _Node[]
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*
278+
* constructor(val?: number, neighbors?: _Node[]) {
254279
* this.val = (val===undefined ? 0 : val)
255280
* this.neighbors = (neighbors===undefined ? [] : neighbors)
256281
* }
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* }
283+
*
258284
*/
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260-
function cloneGraph(node: Node | null): Node | null {
261-
if (node == null) return null;
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263-
const visited = new Map();
264-
visited.set(node, new Node(node.val));
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const queue = [node];
266-
while (queue.length) {
267-
const cur = queue.shift();
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for (let neighbor of cur.neighbors || []) {
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if (!visited.has(neighbor)) {
270-
queue.push(neighbor);
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const newNeighbor = new Node(neighbor.val, []);
272-
visited.set(neighbor, newNeighbor);
273-
}
274-
const newNode = visited.get(cur);
275-
newNode.neighbors.push(visited.get(neighbor));
286+
function cloneGraph(node: _Node | null): _Node | null {
287+
const g: Map<_Node, _Node> = new Map();
288+
const dfs = (node: _Node | null): _Node | null => {
289+
if (!node) {
290+
return null;
276291
}
277-
}
278-
return visited.get(node);
292+
if (g.has(node)) {
293+
return g.get(node);
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}
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const cloned = new _Node(node.val);
296+
g.set(node, cloned);
297+
for (const nxt of node.neighbors) {
298+
cloned.neighbors.push(dfs(nxt));
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}
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return cloned;
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};
302+
return dfs(node);
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}
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```
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#### JavaScript
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```js
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/**
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* // Definition for a _Node.
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* function _Node(val, neighbors) {
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* this.val = val === undefined ? 0 : val;
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* this.neighbors = neighbors === undefined ? [] : neighbors;
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* };
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*/
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/**
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* @param {_Node} node
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* @return {_Node}
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*/
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var cloneGraph = function (node) {
322+
const g = new Map();
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const dfs = node => {
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if (!node) {
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return null;
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}
327+
if (g.has(node)) {
328+
return g.get(node);
329+
}
330+
const cloned = new _Node(node.val);
331+
g.set(node, cloned);
332+
for (const nxt of node.neighbors) {
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cloned.neighbors.push(dfs(nxt));
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}
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return cloned;
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};
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return dfs(node);
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};
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```
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#### C#
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```cs
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using System.Collections.Generic;
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/*
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// Definition for a Node.
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public class Node {
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public int val;
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public IList<Node> neighbors;
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public Node() {
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val = 0;
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neighbors = new List<Node>();
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}
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public Node(int _val) {
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val = _val;
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neighbors = new List<Node>();
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}
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public Node(int _val, List<Node> _neighbors) {
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val = _val;
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neighbors = _neighbors;
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}
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}
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*/
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287367
public class Solution {
288368
public Node CloneGraph(Node node) {
289-
if (node == null) return null;
290-
var dict = new Dictionary<int, Node>();
291-
var queue = new Queue<Node>();
292-
queue.Enqueue(CloneVal(node));
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dict.Add(node.val, queue.Peek());
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while (queue.Count > 0)
295-
{
296-
var current = queue.Dequeue();
297-
var newNeighbors = new List<Node>(current.neighbors.Count);
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foreach (var oldNeighbor in current.neighbors)
299-
{
300-
Node newNeighbor;
301-
if (!dict.TryGetValue(oldNeighbor.val, out newNeighbor))
302-
{
303-
newNeighbor = CloneVal(oldNeighbor);
304-
queue.Enqueue(newNeighbor);
305-
dict.Add(newNeighbor.val, newNeighbor);
306-
}
307-
newNeighbors.Add(newNeighbor);
369+
var g = new Dictionary<Node, Node>();
370+
Node Dfs(Node n) {
371+
if (n == null) {
372+
return null;
373+
}
374+
if (g.ContainsKey(n)) {
375+
return g[n];
308376
}
309-
current.neighbors = newNeighbors;
377+
var cloned = new Node(n.val);
378+
g[n] = cloned;
379+
foreach (var neighbor in n.neighbors) {
380+
cloned.neighbors.Add(Dfs(neighbor));
381+
}
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return cloned;
310383
}
311-
return dict[node.val];
312-
}
313-
314-
private Node CloneVal(Node node)
315-
{
316-
return new Node(node.val, new List<Node>(node.neighbors));
384+
return Dfs(node);
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}
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}
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```

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