### Problem Statement#

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] = [ai, bi]` indicates that you must take course `bi` first if you want to take course `ai`.

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#

``````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.
``````

#### Example 2:#

``````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.
``````

### DFS: Recurisve#

``````from collections import defaultdict
class Solution:
def canFinish(self, numCourses: int, prerequisites: List[List[int]]) -> bool:
seen = set()

for a, b in prerequisites:

if u in seen:
return True

return True