course-schedule

/** https://leetcode.com/problems/course-schedule/
 * @param {number} numCourses
 * @param {number[][]} prerequisites
 * @return {boolean}
 */
var canFinish = function(numCourses, prerequisites) {
    let course_dependencyMap = {};
    let actual = numCourses;
    let solved = false, filtered, curr_key;
    while (--numCourses >= 0) {
        course_dependencyMap[numCourses] = [];
    }

    prerequisites.forEach(prerequisity=>course_dependencyMap[prerequisity[0]].push(prerequisity[1]));

    while (true) {
        filtered = [];
        Object.entries(course_dependencyMap).forEach(([key,values])=>{
          if(values.length === 0){
              actual--;
              delete course_dependencyMap[key];
              filtered.push(Number(key));
          }});
        if (filtered.length === 0) {
            break;
        } else if (filtered.length === actual || !actual) {
            solved = true;
            break;
        };

        Object.entries(course_dependencyMap).forEach(([key,values])=>course_dependencyMap[key] = course_dependencyMap[key].filter(val=>filtered.indexOf(val) === -1));
    }
    ;return solved;
};