leetcode的课程表，定一个变量是啥意思啊，还有这下面几个for循环啥意思啊，有没有好兄弟能稍微帮我讲一下啊！

Question

问题遇到的现象和发生背景

https://leetcode-cn.com/problems/course-schedule/

问题相关代码，请勿粘贴截图

class Solution {
private:
    vector<vector<int>> edges;
    vector<int> indeg;

public:
    bool canFinish(int numCourses, vector<vector<int>>& prerequisites) {
        edges.resize(numCourses);
        indeg.resize(numCourses);
        for (const auto& info: prerequisites) {
            edges[info[1]].push_back(info[0]);
            ++indeg[info[0]];
        }

        queue<int> q;
        for (int i = 0; i < numCourses; ++i) {
            if (indeg[i] == 0) {
                q.push(i);
            }
        }

        int visited = 0;
        while (!q.empty()) {
            ++visited;
            int u = q.front();
            q.pop();
            for (int v: edges[u]) {
                --indeg[v];
                if (indeg[v] == 0) {
                    q.push(v);
                }
            }
        }

        return visited == numCourses;
    }
};

运行结果及报错内容

我的解答思路和尝试过的方法

我想要达到的结果