top-three-repeated.cpp

// C++ Program to Find the top three repeated numbers 
#include <bits/stdc++.h> 
using namespace std; 
  
/* Function to print top three repeated numbers */
void top3Repeated(int arr[], int n) 
{ 
    // There should be atleast two elements 
    if (n < 3) { 
        cout << "Invalid Input"; 
        return; 
    } 
      
    // Count Frequency of each element 
    unordered_map<int, int> fre;  
    for (int i = 0; i < n; i++) 
        fre[arr[i]]++; 
  
    // Initialize first value of each variable 
    // of Pair type is INT_MIN 
    pair<int, int> x, y, z; 
    x.first = y.first = z.first = INT_MIN; 
  
    for (auto curr : fre) { 
  
        // If frequency of current element 
        // is not zero and greater than 
        // frequency of first largest element 
        if (curr.second > x.first) { 
              
            // Update second and third largest 
            z = y; 
            y = x; 
  
            // Modify values of x Number 
            x.first = curr.second; 
            x.second = curr.first; 
        } 
  
        // If frequency of current element is 
        // not zero and frequency of current  
        // element is less than frequency of  
        // first largest element, but greater 
        // than y element 
        else if (curr.second > y.first) { 
  
            // Modify values of third largest 
            z = y; 
  
            // Modify values of second largest 
            y.first = curr.second; 
            y.second = curr.first; 
        } 
  
        // If frequency of current element  
        // is not zero and frequency of 
        // current element is less than  
        // frequency of first element and  
        // second largest, but greater than  
        // third largest.  
        else if (curr.second > z.first) { 
  
            // Modify values of z Number 
            z.first = curr.second; 
            z.second = curr.first; 
        } 
    } 
  
    cout << "Three largest elements are "
        << x.second << " " << y.second  
        << " " << z.second; 
} 
  
// Driver's Code 
int main() 
{ 
    int arr[] = { 3, 4, 2, 3, 16, 3, 15,  
                16, 15, 15, 16, 2, 3 }; 
    int n = sizeof(arr) / sizeof(arr[0]); 
    top3Repeated(arr, n); 
    return 0; 
}