class Solution {
public:
    bool canFinish(int numCourses, vector<vector<int>>& prerequisites) {
        unordered_map<int, int> degree;
        unordered_map<int, unordered_set<int>> graph;

        for (int i = 0; i < numCourses; ++i) {
            degree[i] = 0;
        }

        for (const auto& course: prerequisites) {
            degree[course[0]]++;
            graph[course[1]].insert(course[0]);
        }

        queue<int> q;
        for (int i = 0; i < numCourses; ++i) {
            if (degree[i] == 0) {

                q.push(i);
            }
        }

        while (!q.empty()) {
            int id = q.front(); q.pop();
            numCourses--;

            for (const auto& child : graph[id]) {
                degree[child]--;
                if (degree[child] == 0) {
                    q.push(child);
                }
            }
        }

        return numCourses == 0;
    }
};