Watch 10 video solutions for Find Lucky Integer in an Array, a easy level problem involving Array, Hash Table, Counting. This walkthrough by Technosage has 3,018 views views. Want to try solving it yourself? Practice on FleetCode or read the detailed text solution.
Given an array of integers arr, a lucky integer is an integer that has a frequency in the array equal to its value.
Return the largest lucky integer in the array. If there is no lucky integer return -1.
Example 1:
Input: arr = [2,2,3,4] Output: 2 Explanation: The only lucky number in the array is 2 because frequency[2] == 2.
Example 2:
Input: arr = [1,2,2,3,3,3] Output: 3 Explanation: 1, 2 and 3 are all lucky numbers, return the largest of them.
Example 3:
Input: arr = [2,2,2,3,3] Output: -1 Explanation: There are no lucky numbers in the array.
Constraints:
1 <= arr.length <= 5001 <= arr[i] <= 500