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: 2Explanation: The only lucky number in the array is 2 because frequency[2] == 2.

Example 2:

Input: arr = [1,2,2,3,3,3]Output: 3Explanation: 1, 2 and 3 are all lucky numbers, return the largest of them.

Example 3:

Input: arr = [2,2,2,3,3]Output: -1Explanation: There are no lucky numbers in the array.

Runtime:?10 ms, faster than?13.49%?of?Java?online submissions for?Find Lucky Integer in an Array.

Memory Usage:?43.6 MB, less than?11.76%?of?Java?online submissions for?Find Lucky Integer in an Array.