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feat: add solutions to lc/lcof2 problem: Sequence Reconstruction
lc No.0444.Sequence Reconstruction lcof2 No.115.Sequence Reconstruction
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‎lcof2/剑指 Offer II 113. 课程顺序/README.md

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<p><meta charset="UTF-8" />注意：本题与主站 210&nbsp;题相同：<a href="https://leetcode-cn.com/problems/course-schedule-ii/">https://leetcode-cn.com/problems/course-schedule-ii/</a></p>
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## 解法
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<!-- 这里可写通用的实现逻辑 -->
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拓扑排序，BFS 实现。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class Solution:
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def findOrder(self, numCourses: int, prerequisites: List[List[int]]) -> List[int]:
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edges = collections.defaultdict(list)
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indegree = [0] * numCourses
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for i, j in prerequisites:
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edges[j].append(i)
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indegree[i] += 1
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q = collections.deque()
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for i in range(numCourses):
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if indegree[i] == 0:
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q.append(i)
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res = []
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while q:
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i = q.popleft()
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res.append(i)
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for j in edges[i]:
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indegree[j] -= 1
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if indegree[j] == 0:
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q.append(j)
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return res if len(res) == numCourses else []
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class Solution {
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public int[] findOrder(int numCourses, int[][] prerequisites) {
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List<Integer>[] edges = new List[numCourses];
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for (int i = 0; i < numCourses; ++i) {
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edges[i] = new ArrayList<>();
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}
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int[] indegree = new int[numCourses];
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for (int[] p : prerequisites) {
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edges[p[1]].add(p[0]);
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++indegree[p[0]];
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}
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Queue<Integer> q = new LinkedList<>();
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for (int i = 0; i < numCourses; ++i) {
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if (indegree[i] == 0) {
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q.offer(i);
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}
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}
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int[] res = new int[numCourses];
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int cnt = 0;
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while (!q.isEmpty()) {
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int i = q.poll();
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res[cnt++] = i;
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for (int j : edges[i]) {
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--indegree[j];
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if (indegree[j] == 0) {
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q.offer(j);
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}
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}
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}
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return cnt == numCourses ? res : new int[0];
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}
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}
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```
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### **C++**
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```cpp
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class Solution {
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public:
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vector<int> findOrder(int numCourses, vector<vector<int>>& prerequisites) {
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vector<vector<int>> edges(numCourses);
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vector<int> indegree(numCourses);
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for (auto p : prerequisites)
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{
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edges[p[1]].push_back(p[0]);
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++indegree[p[0]];
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}
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queue<int> q;
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for (int i = 0; i < numCourses; ++i)
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{
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if (indegree[i] == 0) q.push(i);
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}
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vector<int> res;
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while (!q.empty())
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{
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int i = q.front();
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q.pop();
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res.push_back(i);
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for (int j : edges[i])
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{
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--indegree[j];
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if (indegree[j] == 0) q.push(j);
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}
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}
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return res.size() == numCourses ? res : vector<int>();
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}
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};
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```
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### **Go**
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```go
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func findOrder(numCourses int, prerequisites [][]int) []int {
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edges := make([][]int, numCourses)
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indegree := make([]int, numCourses)
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for _, p := range prerequisites {
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edges[p[1]] = append(edges[p[1]], p[0])
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indegree[p[0]]++
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}
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var q []int
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for i := 0; i < numCourses; i++ {
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if indegree[i] == 0 {
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q = append(q, i)
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}
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}
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var res []int
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for len(q) > 0 {
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i := q[0]
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q = q[1:]
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res = append(res, i)
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for _, j := range edges[i] {
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indegree[j]--
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if indegree[j] == 0 {
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q = append(q, j)
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}
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}
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}
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if len(res) == numCourses {
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return res
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}
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return []int{}
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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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public class Solution {
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public int[] FindOrder(int numCourses, int[][] prerequisites) {
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var indegree = new int[numCourses];
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var edgeCount = prerequisites.Length;
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var edge = new List<int>[numCourses];
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for (var i = 0; i < edgeCount; ++i)
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{
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var child = prerequisites[i][0];
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var parent = prerequisites[i][1];
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if (edge[parent] == null)
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{
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edge[parent] = new List<int>();
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}
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edge[parent].Add(child);
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++indegree[child];
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}
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var queue = new Queue<int>();
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for (var i = 0; i < numCourses; ++i)
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{
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if (indegree[i] == 0) queue.Enqueue(i);
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}
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var result = new int[numCourses];
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var count = 0;
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while (queue.Count > 0)
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{
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var node = queue.Dequeue();
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result[count++] = node;
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if (edge[node] != null)
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{
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foreach (var next in edge[node])
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{
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if (--indegree[next] == 0)
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{
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queue.Enqueue(next);
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}
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}
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}
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}
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return count == numCourses ? result : new int[0];
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}
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}
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```
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### **...**

‎lcof2/剑指 Offer II 113. 课程顺序/Solution.cpp

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class Solution {
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public:
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vector<int> findOrder(int numCourses, vector<vector<int>>& prerequisites) {
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vector<vector<int>> edges(numCourses);
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vector<int> indegree(numCourses);
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for (auto p : prerequisites)
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{
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edges[p[1]].push_back(p[0]);
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++indegree[p[0]];
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}
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queue<int> q;
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for (int i = 0; i < numCourses; ++i)
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{
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if (indegree[i] == 0) q.push(i);
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}
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vector<int> res;
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while (!q.empty())
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{
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int i = q.front();
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q.pop();
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res.push_back(i);
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for (int j : edges[i])
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{
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--indegree[j];
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if (indegree[j] == 0) q.push(j);
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}
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}
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return res.size() == numCourses ? res : vector<int>();
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}
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};

‎lcof2/剑指 Offer II 113. 课程顺序/Solution.cs

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using System.Collections.Generic;
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public class Solution {
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public int[] FindOrder(int numCourses, int[][] prerequisites) {
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var indegree = new int[numCourses];
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var edgeCount = prerequisites.Length;
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var edge = new List<int>[numCourses];
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for (var i = 0; i < edgeCount; ++i)
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{
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var child = prerequisites[i][0];
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var parent = prerequisites[i][1];
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if (edge[parent] == null)
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{
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edge[parent] = new List<int>();
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}
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edge[parent].Add(child);
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++indegree[child];
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}
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var queue = new Queue<int>();
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for (var i = 0; i < numCourses; ++i)
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{
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if (indegree[i] == 0) queue.Enqueue(i);
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}
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var result = new int[numCourses];
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var count = 0;
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while (queue.Count > 0)
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{
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var node = queue.Dequeue();
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result[count++] = node;
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if (edge[node] != null)
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{
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foreach (var next in edge[node])
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{
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if (--indegree[next] == 0)
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{
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queue.Enqueue(next);
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}
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}
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}
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}
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return count == numCourses ? result : new int[0];
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}
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}

‎lcof2/剑指 Offer II 113. 课程顺序/Solution.go

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func findOrder(numCourses int, prerequisites [][]int) []int {
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edges := make([][]int, numCourses)
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indegree := make([]int, numCourses)
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for _, p := range prerequisites {
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edges[p[1]] = append(edges[p[1]], p[0])
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indegree[p[0]]++
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}
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var q []int
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for i := 0; i < numCourses; i++ {
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if indegree[i] == 0 {
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q = append(q, i)
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}
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}
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var res []int
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for len(q) > 0 {
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i := q[0]
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q = q[1:]
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res = append(res, i)
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for _, j := range edges[i] {
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indegree[j]--
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if indegree[j] == 0 {
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q = append(q, j)
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}
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}
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}
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if len(res) == numCourses {
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return res
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}
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return []int{}
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}

‎lcof2/剑指 Offer II 113. 课程顺序/Solution.java

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class Solution {
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public int[] findOrder(int numCourses, int[][] prerequisites) {
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List<Integer>[] edges = new List[numCourses];
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for (int i = 0; i < numCourses; ++i) {
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edges[i] = new ArrayList<>();
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}
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int[] indegree = new int[numCourses];
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for (int[] p : prerequisites) {
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edges[p[1]].add(p[0]);
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++indegree[p[0]];
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}
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Queue<Integer> q = new LinkedList<>();
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for (int i = 0; i < numCourses; ++i) {
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if (indegree[i] == 0) {
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q.offer(i);
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}
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}
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int[] res = new int[numCourses];
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int cnt = 0;
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while (!q.isEmpty()) {
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int i = q.poll();
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res[cnt++] = i;
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for (int j : edges[i]) {
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--indegree[j];
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if (indegree[j] == 0) {
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q.offer(j);
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}
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}
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}
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return cnt == numCourses ? res : new int[0];
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}
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}

‎lcof2/剑指 Offer II 113. 课程顺序/Solution.py

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class Solution:
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def findOrder(self, numCourses: int, prerequisites: List[List[int]]) -> List[int]:
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edges = collections.defaultdict(list)
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indegree = [0] * numCourses
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for i, j in prerequisites:
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edges[j].append(i)
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indegree[i] += 1
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q = collections.deque()
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for i in range(numCourses):
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if indegree[i] == 0:
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q.append(i)
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res = []
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while q:
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i = q.popleft()
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res.append(i)
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for j in edges[i]:
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indegree[j] -= 1
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if indegree[j] == 0:
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q.append(j)
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return res if len(res) == numCourses else []

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