Description
Given an undirected star graph (a center node connected to all others), find and return the center of the graph.
Examples
Input:
edges = [[1,2],[2,3],[4,2]]Output:
2Explanation:
Node 2 appears in all edges: [1,2], [2,3], [4,2]. In a star graph, the center connects to every other node.
Input:
edges = [[5,7],[6,7],[7,8]]Output:
7Explanation:
Edges=[[5,7],[6,7],[7,8]]: Check first two edges [5,7] and [6,7]. Node 7 appears in both (position [1] in first edge, position [1] in second edge). Since the center must appear in every edge, node 7 is the center.
Input:
edges = [[3,9],[9,1],[9,4],[2,9],[9,10]]Output:
9Explanation:
Edges=[[3,9],[9,1],[9,4],[2,9],[9,10]]: Check first two edges [3,9] and [9,1]. Node 9 appears in both (position [1] in first, position [0] in second). The center node 9 connects to all leaf nodes: 3, 1, 4, 2, and 10.
Constraints
- •
3 ≤ n ≤ 10⁵