Merge pull request #2598 from KaiserTT/master

更新了图论-拓扑排序精讲-0117.软件构建的 Java 和 Python 版本代码

problems/kamacoder/0117.软件构建.md

@@ -167,7 +167,7 @@
 
 ![](https://code-thinking-1253855093.file.myqcloud.com/pics/20240510114004.png) 
 
--------------- 
+--------------
 
 后面的过程一样的，节点3 和 节点4，入度都为0，选哪个都行。 
 
@@ -344,8 +344,107 @@ int main() {
 
 ### Java 
 
+```java
+import java.util.*;
+
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner(System.in);
+        int n = scanner.nextInt();
+        int m = scanner.nextInt();
+
+        List<List<Integer>> umap = new ArrayList<>(); // 记录文件依赖关系
+        int[] inDegree = new int[n]; // 记录每个文件的入度
+
+        for (int i = 0; i < n; i++)
+            umap.add(new ArrayList<>());
+
+        for (int i = 0; i < m; i++) {
+            int s = scanner.nextInt();
+            int t = scanner.nextInt();
+            umap.get(s).add(t); // 记录s指向哪些文件
+            inDegree[t]++; // t的入度加一
+        }
+
+        Queue<Integer> queue = new LinkedList<>();
+        for (int i = 0; i < n; i++) {
+            if (inDegree[i] == 0) {
+                // 入度为0的文件，可以作为开头，先加入队列
+                queue.add(i);
+            }
+        }
+
+        List<Integer> result = new ArrayList<>();
+
+        // 拓扑排序
+        while (!queue.isEmpty()) {
+            int cur = queue.poll(); // 当前选中的文件
+            result.add(cur);
+            for (int file : umap.get(cur)) {
+                inDegree[file]--; // cur的指向的文件入度-1
+                if (inDegree[file] == 0) {
+                    queue.add(file);
+                }
+            }
+        }
+
+        if (result.size() == n) {
+            for (int i = 0; i < result.size(); i++) {
+                System.out.print(result.get(i));
+                if (i < result.size() - 1) {
+                    System.out.print(" ");
+                }
+            }
+        } else {
+            System.out.println(-1);
+        }
+    }
+}
+```
+
+
+
 ### Python
 
+```python
+from collections import deque, defaultdict
+
+def topological_sort(n, edges):
+    inDegree = [0] * n # inDegree 记录每个文件的入度
+    umap = defaultdict(list) # 记录文件依赖关系
+
+    # 构建图和入度表
+    for s, t in edges:
+        inDegree[t] += 1
+        umap[s].append(t)
+
+    # 初始化队列，加入所有入度为0的节点
+    queue = deque([i for i in range(n) if inDegree[i] == 0])
+    result = []
+
+    while queue:
+        cur = queue.popleft()  # 当前选中的文件
+        result.append(cur)
+        for file in umap[cur]:  # 获取该文件指向的文件
+            inDegree[file] -= 1  # cur的指向的文件入度-1
+            if inDegree[file] == 0:
+                queue.append(file)
+
+    if len(result) == n:
+        print(" ".join(map(str, result)))
+    else:
+        print(-1)
+
+
+if __name__ == "__main__":
+    n, m = map(int, input().split())
+    edges = [tuple(map(int, input().split())) for _ in range(m)]
+    topological_sort(n, edges)
+```
+
+
+
 ### Go
 
 ### Rust