updated solution

LeetCode/1346_Check_if_N_and_its_Double_Exist.py

@@ -1,14 +1,9 @@
 class Solution:
- def tribonacci(self, n: int) -> int:
- a, b, c = 0, 1, 1
- if n == 0:
- return 0
- elif n == 1 or n == 2:
- return 1
- else:
- for _ in range(n - 2):
- temp = a + b + c
- a = b
- b = c
- c = temp
- return temp
+ def checkIfExist(self, arr: List[int]) -> bool:
+
+ seen = set()
+ for x in arr:
+ if x * 2 in seen or (not x % 2 and x // 2 in seen):
+ return True
+ seen.add(x)
+ return False