Solution (leetcode-in-java 1.21 API)

java.lang.Object
- g2301_2400.s2316_count_unreachable_pairs_of_nodes_in_an_undirected_graph.Solution

```
public class Solution
extends Object
```
2316 - Count Unreachable Pairs of Nodes in an Undirected Graph.
Medium

You are given an integer n. There is an undirected graph with n nodes, numbered from 0 to n - 1. You are given a 2D integer array edges where edges[i] = [a_i, b_i] denotes that there exists an undirected edge connecting nodes a_i and b_i.

Return the number of pairs of different nodes that are unreachable from each other.

Example 1:

Input: n = 3, edges = [[0,1],[0,2],[1,2]]

Output: 0

Explanation: There are no pairs of nodes that are unreachable from each other.

Therefore, we return 0.

Example 2:

Input: n = 7, edges = [[0,2],[0,5],[2,4],[1,6],[5,4]]

Output: 14

Explanation: There are 14 pairs of nodes that are unreachable from each other: [[0,1],[0,3],[0,6],[1,2],[1,3],[1,4],[1,5],[2,3],[2,6],[3,4],[3,5],[3,6],[4,6],[5,6]].

Therefore, we return 14.

Constraints:
- 1 <= n <= 10⁵
- 0 <= edges.length <= 2 * 10⁵
- edges[i].length == 2
- 0 <= a_i, b_i < n
- a_i != b_i
- There are no repeated edges.

- Constructor Summary
  
  Constructors
  Constructor Description
  
  Solution()
- Method Summary
  
  All Methods Instance Methods Concrete Methods
  Modifier and Type Method Description
  
  long countPairs(int n, int[][] edges)
  - Methods inherited from class java.lang.Object
    clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail
- Solution
```
public Solution()
```

Method Detail

countPairs

public long countPairs(int n,
                       int[][] edges)