Welcome to the daily solving of our PROBLEM OF THE DAY with Siddharth Hazra. We will discuss the entire problem step-by-step and work towards developing an optimized solution. This will not only help you brush up on your concepts of Array but also build up problem-solving skills.

In this problem, we are given an array of n integers. Find the first element that occurs atleast k number of times. If no such element exists in the array, then expect the answer to be -1.

Example :

Input :
n = 7, k = 2
a[] = {1, 7, 4, 3, 4, 8, 7}
Output :
4
Explanation :
Both 7 and 4 occur 2 times. But 4 is first that occurs twice. As at index = 4, 4 has occurred twice whereas 7 appeared twice at index 6.

Give the problem a try before going through the video. All the best!!!
Problem Link: https://www.geeksforgeeks.org/problems/first-element-to-occur-k-times5150/1