0323__number_of_connected_components_in_an_undirected_graph.md

Number of Connected Components in an Undirected Graph

LeetCode https://leetcode.com/problems/number-of-connected-components-in-an-undirected-graph/description/

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.

Example 1

graph LR
    0 --- 1
    1 --- 2
    
    3 --- 4

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Input:

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

Output: 2

Example 2

graph LR
    0 --- 1
    1 --- 2
    2 --- 3
    3 --- 4

Loading

Input:

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

Output: 1

Constraints

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