找出星型图的中心节点

/*
 * Approach: In a star graph, one node is the center, connected to all others.
 * We find the center by looking at the first two edges. The common node in these two edges is the center.
 * Using Java Streams, we can find this node efficiently.
 */
import java.util.Arrays;
public class Solution {
    public int findCenter(int[][] edges) {
        return Arrays.stream(edges)
            .flatMapToInt(e -> Arrays.stream(new int[]{e[0], e[1]}))
            .distinct()
            .filter(n -> Arrays.stream(edges)
                .allMatch(e -> e[0] == n || e[1] == n))
            .findFirst()
            .getAsInt();
    }
}