Package g1401_1500.s1466_reorder_routes_to_make_all_paths_lead_to_the_city_zero

Class Solution

java.lang.Object
g1401_1500.s1466_reorder_routes_to_make_all_paths_lead_to_the_city_zero.Solution
public class Solution extends Object
1466 - Reorder Routes to Make All Paths Lead to the City Zero\. Medium There are `n` cities numbered from `0` to `n - 1` and `n - 1` roads such that there is only one way to travel between two different cities (this network form a tree). Last year, The ministry of transport decided to orient the roads in one direction because they are too narrow. Roads are represented by `connections` where connections[i] = [ai, bi] represents a road from city ai to city bi. This year, there will be a big event in the capital (city `0`), and many people want to travel to this city. Your task consists of reorienting some roads such that each city can visit the city `0`. Return the **minimum** number of edges changed. It's **guaranteed** that each city can reach city `0` after reorder. **Example 1:** ![](https://assets.leetcode.com/uploads/2020/05/13/sample_1_1819.png) **Input:** n = 6, connections = \[\[0,1],[1,3],[2,3],[4,0],[4,5]] **Output:** 3 **Explanation:** Change the direction of edges show in red such that each node can reach the node 0 (capital). **Example 2:** ![](https://assets.leetcode.com/uploads/2020/05/13/sample_2_1819.png) **Input:** n = 5, connections = \[\[1,0],[1,2],[3,2],[3,4]] **Output:** 2 **Explanation:** Change the direction of edges show in red such that each node can reach the node 0 (capital). **Example 3:** **Input:** n = 3, connections = \[\[1,0],[2,0]] **Output:** 0 **Constraints:** * 2 <= n <= 5 * 104 * `connections.length == n - 1` * `connections[i].length == 2` * 0 <= ai, bi <= n - 1 * ai != bi

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • minReorder

      public int minReorder(int n, int[][] connections)