---
title: '207. Course Schedule'
description: 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
sidebar:
  label: 'Course Schedule'
  badge: 'Medium'
---

<Badge variant="accent">Depth-First Search</Badge>

### 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.

### Constraints:

- `1 <= numCourses <= 2000`
- `0 <= prerequisites.length <= 5000`
- `prerequisites[i].length == 2`
- `0 <= ai, bi < numCourses`
- All the pairs `prerequisites[i]` are unique.

## Solution

```py
class Solution:
    def canFinish(self, numCourses: int, prerequisites: list[list[int]]) -> bool:
```