Find Lucky Integer in an Array
You are 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 = [1,2,2,3,3,3]
Output: 3Explanation: 1, 2 and 3 are all lucky numbers, 3 is the largest.
Example 2:
Input: arr = [2,2,2,3,3]
Output: -1Constraints:
1 <= arr.length <= 5001 <= arr[i] <= 500