Completed Graph-3

Find the Celebrity.py

@@ -0,0 +1,33 @@
+# The knows API is already defined for you.
+# return a bool, whether a knows b
+# def knows(a: int, b: int) -> bool:
+
+class Solution:
+    def findCelebrity(self, n: int) -> int:
+        #Brute Force Approach
+        # Time O(n**2)
+        # Space O(n)
+        # arr = [0 for i in range(n)]
+        # for i in range(n):
+        #     for j in range(n):
+        #         if i!=j:
+        #             if knows(j,i): arr[i] += 1
+        #             if knows(i,j):
+        #                 arr[i] -= 1
+        #                 break
+        # # print(arr)
+        # for i in range(len(arr)):
+        #     if arr[i] == n-1: return i
+        # return -1
+
+        # Optimal Approach
+        # Time O(n)
+        # Space O(1)
+        celeb = 0
+        for i in range(1,n):
+            if knows(celeb, i): celeb = i
+        # print(celeb)
+        for i in range(n):
+            if i==celeb: continue
+            if not knows(i, celeb) or knows(celeb, i): return -1
+        return celeb