Most frequent element in an array in C++

In this tutorial, we are going to write a program that finds the most frequent element in an array.

Let's see the steps to solve the problem.

Initialise the array.
Initialise a map to store the frequency of each element.
Count the frequency of each element and store it in the map.
Iterate over the map and find the element with most frequency.

Example

Let's see the code.

#include <bits/stdc++.h>
using namespace std;
int getMostFrequentNumber(int arr[], int n) {
   unordered_map<int, int> elements;
   for (int i = 0; i < n; i++) {
      elements[arr[i]]++;
   }
   int maxCount = 0, res = -1;
   for (auto i : elements) {
      if (maxCount < i.second) {
         res = i.first;
         maxCount = i.second;
      }
   }
   return res;
}
int main() {
   int arr[] = { 1, 2, 3, 3, 2, 2, 1, 1, 2, 3, 4 };
   int n = 11;
   cout << getMostFrequentNumber(arr, n) << endl;
   return 0;
}

Output

If you run the above code, then you will get the following result.

Conclusion

If you have any queries in the tutorial, mention them in the comment section.

Hafeezul Kareem

Published on 01-Jul-2021 06:24:27

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