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] <= 500class Solution {
public int findLucky(int[] arr) {
int[] freq = new int[501];
int maxI = 0;
for (int i : arr) {
freq[i]++;
maxI = Math.max(maxI, i);
}
for (int i = maxI; i > 0; i--)
if (freq[i] == i)
return i;
return -1;
}
}