我用Java刷 leetcode 690. 员工的重要性

Posted 2021-06-02 深林无鹿

我的垃圾AC（脑溢血级别bfs 因为忘记用哈希表）：

/*
// Definition for Employee.
class Employee {
    public int id;
    public int importance;
    public List<Integer> subordinates;
};
*/

class Solution {
    public int getImportance(List<Employee> employees, int id) {
        int res = 0;
        Queue<Employee> queue = new LinkedList<>();
        for (Employee e: employees) {
            if (e.id == id) {
                queue.offer(e);
            }
        }
        while (queue.peek() != null) {
            Employee e = queue.poll();
            res += e.importance;
            for (int val : e.subordinates) {
                for (Employee emp : employees) {
                    if (emp.id == val) {
                        queue.offer(emp);
                    }
                }
            }
        }
        return res;
    }
}

我的改进DFS：AC时间100%

/*
// Definition for Employee.
class Employee {
    public int id;
    public int importance;
    public List<Integer> subordinates;
};
*/

class Solution {
    private Map<Integer, Employee> hashMap = new HashMap<Integer, Employee>();
    public int getImportance(List<Employee> employees, int id) {
        for (Employee e : employees) {
            hashMap.put(e.id, e);
        }
        return dfs(id);
    }
    public int dfs(int id) {
        Employee e = hashMap.get(id);
        int total = e.importance;
        for (int tid : e.subordinates) {
            total += dfs(tid);
        }
        return total;
    }
}