How to Find the Mode of Numbers in a Sorted Array in C?

Last Updated : 18 Jun, 2024

The mode of the given numbers can be defined as the value that occurs the most in the given dataset or the value with the highest frequency. In this article, we will learn how to find the mode of all elements in a sorted array of integers in C.

Example:

Input:
myArray = {1, 2, 3, 3, 5, 5, 5, 5, 6, 7}

Output:
Mode is 5

Calculate the Mode of a Sorted Array in C

We can calculate the mode of the sorted array by counting the frequency of the adjacent elements as in a sorted array, all the equal numbers will be next to each other.

Approach

Initialize an array with integer values.
Initialize variables mode, curr_count, and max_count to track mode.
Start iterating the array.
If the current element is the same as the previous one, curr_count is incremented.
If the current element is different, it checks if curr_count is greater than max_count.
If it is, max_count and mode are updated.
curr_count is then reset to 1 for the new element.
Check if the last element forms the mode.
Print the mode or a message if no mode is found.

C Program to Find the Mode of the Sorted Array

#include <stdio.h>

int main() 
{ 
    // Initialize an array with integer values 
    int myArray[] = { 1, 2, 3, 3, 5, 5, 5, 5, 6, 7 }; 
    int size = sizeof(myArray) / sizeof(myArray[0]); 

    // Initialize variables to track mode 
    int mode = -1; 
    int curr_count = 1; 
    int max_count = 1; 

    // Iterate through the array to find the mode 
    for (int i = 1; i < size; ++i) { 
        if (myArray[i] == myArray[i - 1]) { 
            ++curr_count; 
        } 
        else { 
            // Check if the current count is greater than 
            // the maximum count found so far 
            if (curr_count > max_count) { 
                max_count = curr_count; 
                mode = myArray[i - 1]; // Update the mode 
            } 
            curr_count = 1; // Reset current count for the 
                            // new element 
        } 
    } 

    // Check if the last element forms the mode 
    if (curr_count > max_count) { 
        mode = myArray[size - 1]; 
    } 

    // Print the mode or a message if no mode is found 
    if (mode != -1) { 
        printf("Mode is: %d" , mode) ; 
    } 
    else { 
        printf( "No mode found.") ; 
    } 

    return 0; 
}

Output

Mode is: 5

Time Complexity: O(n), where n is the elements of the sorted array.
Space Complexity: O(1)