Day 15: LeetCode 1394 [Find Lucky Integer in an Array]
Problem Description: 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 <= 500 1 <= arr[i] <= 500
Link to LeetCode Problem: https://leetcode.com/problems/find-lucky-integer-in-an-array/description/
My thought process: learned about hashmap
