1791. Find Center of Star Graph

Easy
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.
You are given a 2D integer array edges where each edges[i] = [ui, vi] indicates that there is an edge between the nodes ui and vi. Return the center of the given star graph.
Example 1:
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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.
Example 2:
Input: edges = [[1,2],[5,1],[1,3],[1,4]]
Output: 1
Constraints:
  • 3 <= n <= 10^5
  • edges.length == n - 1
  • edges[i].length == 2
  • 1 <= ui, vi <= n
  • ui != vi
  • The given edges represent a valid star graph.

解題

func findCenter(edges [][]int) int {
n := len(edges)
indegree := make([]int, n + 1)
for _, edge := range edges {
indegree[edge[0] - 1]++
indegree[edge[1] - 1]++
​
if indegree[edge[0] - 1] == n {
return edge[0]
}
​
if indegree[edge[1] - 1] == n {
return edge[1]
}
}
​
return 0
}