Added Find Center of Star Graph.java

varunu28 · web-flow · commit d562796de13f · 2021-03-14T12:35:54.000-07:00
diff --git a/Medium/Find Center of Star Graph.java b/Medium/Find Center of Star Graph.java
@@ -0,0 +1,13 @@
+import java.util.Map.Entry;
+
+class Solution {
+  public int findCenter(int[][] edges) {
+    Map<Integer, Set<Integer>> map = new HashMap<>();
+    for (int[] edge : edges) {
+      map.computeIfAbsent(edge[0], k -> new HashSet<>()).add(edge[1]);
+      map.computeIfAbsent(edge[1], k -> new HashSet<>()).add(edge[0]);
+    }
+    return map.entrySet().stream().filter(entry -> entry.getValue().size() == edges.length).map(
+        Entry::getKey).findFirst().orElse(-1);
+  }
+}
