Number of Connected Components in an Undirected Graph

You have a graph of n nodes. You are given an integer n and an array edges where edges[i] = [ai, bi] indicates that there is an edge between ai and bi in the graph.

Return the number of connected components in the graph.

Examples

Example 1:

Input: n = 5, edges = [[0,1],[1,2],[3,4]]

Output: 2

Explanation: There are two connected components: {0, 1, 2} and {3, 4}.

Example 2:

Input: n = 5, edges = [[0,1],[1,2],[2,3],[3,4]]

Output: 1

Explanation: All nodes are connected through a chain, forming one component.

Example 3:

Input: n = 4, edges = []

Output: 4

Explanation: With no edges, each node is its own connected component.

Constraints

• 1 <= n <= 2000
• 0 <= edges.length <= 5000
• edges[i].length == 2
• 0 <= ai, bi < n
• ai != bi
• There are no repeated edges.