There is an undirected star graph consisting of
n nodes labeled from
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.
You are given a 2D integer array
edges where each indicates that there is an edge between the nodes and . Return the center of the given star graph.
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.
Input: edges = [[1,2],[5,1],[1,3],[1,4]] Output: 1
edges.length == n - 1
edges[i].length == 2
1<= , <=
edgesrepresent a valid star graph.
class Solution: def findCenter(self, edges: List[List[int]]) -> int: _dict=defaultdict(list) for n1,n2 in edges: _dict[n1].append(n2) _dict[n2].append(n1) for k,v in _dict.items(): if len(_dict[k])==len(edges): return k