< Back 1394. Find Lucky Integer in an Array 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.