Reverse Graph

Given a directed graph represented as an adjacency list, return its reverse so if an edge goes from A to B, it now goes from B to A.

Each list in the adjacency list should be sorted in ascending order.

Constraints

• 0 ≤ n, m ≤ 250 where n is the number of rows and m is the maximum number of columns in graph

https://binarysearch.com/problems/Reverse-Graph

Examples

Example 1

Input

• graph = [[1], [2], []]

Output

• answer = [[], [0], [1]]

Explanation

In this example the nodes start off 0 -> 1 -> 2 and then become 0 <- 1 <- 2.

Solution