README.md

1791. Find Center of Star Graph

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:

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 <= 105
• edges.length == n - 1
• edges[i].length == 2
• 1 <= ui, vi <= n
• ui != vi
• The given edges represent a valid star graph.

Solutions (Ruby)

1. Solution

# @param {Integer[][]} edges
# @return {Integer}
def find_center(edges)
  edges[0].include?(edges[1][0]) ? edges[1][0] : edges[1][1]
end

Solutions (Rust)

1. Solution

impl Solution {
    pub fn find_center(edges: Vec<Vec<i32>>) -> i32 {
        if edges[0].contains(&edges[1][0]) {
            edges[1][0]
        } else {
            edges[1][1]
        }
    }
}