1462 - Course Schedule IV.

Medium

There are a total of numCourses courses you have to take, labeled from 0 to numCourses - 1. You are given an array prerequisites where <code>prerequisitesi = a_i, b_i</code> indicates that you must take course <code>a_i</code> first if you want to take course <code>b_i</code>.

• For example, the pair [0, 1] indicates that you have to take course 0 before you can take course 1.

Prerequisites can also be indirect. If course a is a prerequisite of course b, and course b is a prerequisite of course c, then course a is a prerequisite of course c.

You are also given an array queries where <code>queriesj = u_j, v_j</code>. For the <code>j^th</code> query, you should answer whether course <code>u_j</code> is a prerequisite of course <code>v_j</code> or not.

Return a boolean array answer, where answer[j] is the answer to the <code>j^th</code> query.

Example 1:

Input: numCourses = 2, prerequisites = [1,0], queries = [0,1,1,0]

Output: false,true

Explanation: The pair 1, 0 indicates that you have to take course 1 before you can take course 0. Course 0 is not a prerequisite of course 1, but the opposite is true.

Example 2:

Input: numCourses = 2, prerequisites = [], queries = [1,0,0,1]

Output: false,false

Explanation: There are no prerequisites, and each course is independent.

Example 3:

Input: numCourses = 3, prerequisites = [1,2,1,0,2,0], queries = [1,0,1,2]

Output: true,true

Constraints:

• 2 <= numCourses <= 100

• 0 <= prerequisites.length <= (numCourses * (numCourses - 1) / 2)

• prerequisites[i].length == 2

• <code>0 <= a_i, b_i<= n - 1</code>

• <code>a_i != b_i</code>

• All the pairs <code>a_i, b_i</code> are unique.

• The prerequisites graph has no cycles.

• <code>1 <= queries.length <= 10⁴</code>

• <code>0 <= u_i, v_i<= n - 1</code>

• <code>u_i != v_i</code>