#323

Number of Connected Components in an Undirected Graph

medium· Graphsruns: 0

You have an undirected graph of n nodes labeled 0 to n - 1. You are given the integer n and an array edges where each edges[i] = [a, b] indicates an undirected edge between a and b. Return the number of connected components in the graph.

wpm 0acc 100%time 0:000 / 501

class Solution:
    def countComponents(
        self, n: int, edges: list[list[int]]
    ) -> int:
        parent = list(range(n))

        def find(x: int) -> int:
            while parent[x] != x:
                parent[x] = parent[parent[x]]
                x = parent[x]
            return x

        components = n
        for a, b in edges:
            ra, rb = find(a), find(b)
            if ra != rb:
                parent[ra] = rb
                components -= 1
        return components

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