Find Center of Star Graph — LeetCode 1791 Python Solution

The problem

There is an undirected star graph consisting of n nodes labeled from 1 to n. A star graph is a graph where there is one center node and exactly n - 1 edges that connect the center node with every other node.

Example

Input

edges = [[1,2],[2,3],[4,2]]

Output

2

Explanation

As shown in the figure above, node 2 is connected to every other node, so 2 is the center.

Python solution

class Solution:
    def findCenter(self, edges: List[List[int]]) -> int:
        return edges[0][0] if edges[0][0] in edges[1] else edges[0][1]

Complexity

Pattern: Depth-First Search

Follow one path to its end before trying the next — the default way to explore a graph. LeetCode 1791. Find Center of Star Graph is filed here on both counts: the reference solution below belongs to the algorithm family this hub collects, and LeetCode tags it Graph.

The depth-first search guide has the Python template for the pattern and the 366 LeetCode problems that use it.

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