A lucky integer is one that its interger value is the same as its frequency in the input array. Return the largets lucky integer or, if there isn’t one, return -1.
The solution is as follows:
from collections import Counter
class Solution:
def findLucky(self, arr: List[int]) -> int:
counts = Counter(arr)
ans = -1
for num, count in counts.items():
if num == count:
ans = max(ans, num)
return ans_ Time Complexity:
O(n) - We have to iterate through the entire input array.
_ Space Complexity:
O(n) - We store the frequency of each number in the input array.