https://leetcode.cn/problems/course-schedule/

Author: masx200

README.md

@@ -10,6 +10,8 @@ leetcode 测试
 
 ##### 包含的内容如下
 
+https://leetcode.cn/problems/course-schedule/
+
 https://leetcode.cn/problems/QA2IGt/
 
 https://leetcode.cn/problems/course-schedule-ii/

course-schedule/index.ts

@@ -0,0 +1,35 @@
+export default function canFinish(
+    numCourses: number,
+    prerequisites: number[][],
+): boolean {
+    const dependents: Map<number, number[]> = new Map();
+    //  const dependents: number[][] = new Array(numCourses).fill(0).map(() => []);
+    const indegress: Map<number, number> = new Map();
+    // const indegress: number[] = new Array(numCourses).fill(0);
+    for (const [child, parent] of prerequisites) {
+        const array = dependents.get(parent) ?? [];
+        array.push(child);
+        dependents.set(parent, array);
+
+        // dependents[parent].push(child);
+        indegress.set(child, (indegress.get(child) ?? 0) + 1);
+        // indegress[child]++;
+    }
+    const queue: number[] = Array.from(Array(numCourses).fill(0).keys()).filter(
+        (i) => !indegress.has(i),
+    );
+
+    const result: number[] = [];
+    while (queue.length) {
+        const u = queue.shift() as number;
+        result.push(u);
+        /* dependents[u] */
+        for (const v of dependents.get(u) ?? []) {
+            const degree = (indegress.get(v) ?? 0) - 1;
+            // indegress[v]--;
+            indegress.set(v, degree);
+            if (degree === 0) queue.push(v);
+        }
+    }
+    return result.length === numCourses;
+}