207-course-schedule

DevGod

Vtuber

Caution

DevGod needs to write an editorial for this problem!

js

/**
 * @param {number} numCourses
 * @param {number[][]} prerequisites
 * @return {boolean}
 */
var canFinish = function (numCourses, prerequisites) {
    const indegree = new Array(numCourses).fill(0);
    const queue = [];

    for (const [course, prereq] of prerequisites) {
        indegree[course] += 1;
    }
    for (let i = 0; i < indegree.length; i++) {
        if (indegree[i] === 0) {
            queue.push(i);
        }
    }
    let count = 0;
    while (queue.length !== 0) {
        const node = queue.pop();
        count += 1;

        for (const [course, prereq] of prerequisites) {
            if (prereq === node) {
                indegree[course] -= 1;
                if (indegree[course] === 0) {
                    queue.push(course);
                }
            }
        }
    }
    return count === numCourses;
};