Package g2301_2400.s2316_count_unreachable_pairs_of_nodes_in_an_undirected_graph

Class Solution

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.<p>Medium</p> <p>You are given an integer <code>n</code>. There is an <strong>undirected</strong> graph with <code>n</code> nodes, numbered from <code>0</code> to <code>n - 1</code>. You are given a 2D integer array <code>edges</code> where <code>edges[i] = [a<sub>i</sub>, b<sub>i</sub>]</code> denotes that there exists an <strong>undirected</strong> edge connecting nodes <code>a<sub>i</sub></code> and <code>b<sub>i</sub></code>.</p> <p>Return <em>the <strong>number of pairs</strong> of different nodes that are <strong>unreachable</strong> from each other</em>.</p> <p><strong>Example 1:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2022/05/05/tc-3.png" alt="" /></p> <p><strong>Input:</strong> n = 3, edges = [[0,1],[0,2],[1,2]]</p> <p><strong>Output:</strong> 0</p> <p><strong>Explanation:</strong> There are no pairs of nodes that are unreachable from each other.</p> <p>Therefore, we return 0.</p> <p><strong>Example 2:</strong></p> <p><img src="https://assets.leetcode.com/uploads/2022/05/05/tc-2.png" alt="" /></p> <p><strong>Input:</strong> n = 7, edges = [[0,2],[0,5],[2,4],[1,6],[5,4]]</p> <p><strong>Output:</strong> 14</p> <p><strong>Explanation:</strong> 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]].</p> <p>Therefore, we return 14.</p> <p><strong>Constraints:</strong></p> <ul> <li><code>1 <= n <= 10<sup>5</sup></code></li> <li><code>0 <= edges.length <= 2 * 10<sup>5</sup></code></li> <li><code>edges[i].length == 2</code></li> <li><code>0 <= a<sub>i</sub>, b<sub>i</sub> < n</code></li> <li><code>a<sub>i</sub> != b<sub>i</sub></code></li> <li>There are no repeated edges.</li> </ul>

  • Constructor Details

    • Solution

      public Solution()

  • Method Details

    • countPairs

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