cpp-flashcards/org/study_deck_02/dsa/graphs/0207-course-schedule.org

#+ANKI_DECK: study_deck_02
* TODO 0207. Course Schedule :medium:
:PROPERTIES:
:NEETCODE: [[file:../../roadmap.org::*0207. Course Schedule][0207. Course Schedule]]
:END:

There are a total of ~numCourses~ courses you have to take, labeled from ~0~ to ~numCourses - 1~. You are given an array ~prerequisites~ where ~prerequisites[i] = [a_{i}, b_{i}]~ indicates that you *must* take course ~b_{i}~ first if you want to take course ~a_{i}~.

 - For example, the pair ~[0, 1]~, indicates that to take course ~0~ you have to first take course ~1~.

Return ~true~ if you can finish all courses. Otherwise, return ~false~.

*Example 1:*


#+begin_src
Input: numCourses = 2, prerequisites = [[1,0]]
Output: true
Explanation: There are a total of 2 courses to take. 
To take course 1 you should have finished course 0. So it is possible.
#+end_src


*Example 2:*


#+begin_src
Input: numCourses = 2, prerequisites = [[1,0],[0,1]]
Output: false
Explanation: There are a total of 2 courses to take. 
To take course 1 you should have finished course 0, and to take course 0 you should also have finished course 1. So it is impossible.
#+end_src


*Constraints:*

 - ~1 <= numCourses <= 2000~

 - ~0 <= prerequisites.length <= 5000~

 - ~prerequisites[i].length == 2~

 - ~0 <= a_{i}, b_{i} < numCourses~

 - All the pairs prerequisites[i] are *unique*.

** TODO Approach
Write your approach here.

** TODO Python
#+begin_src python
class Solution:
    def canFinish(self, numCourses: int, prerequisites: List[List[int]]) -> bool:
#+end_src

** TODO C++
#+begin_src cpp
class Solution {
public:
    bool canFinish(int numCourses, vector<vector<int>>& prerequisites) {
        
    }
};
#+end_src