C Exercises: Find the maximum for each and every contigious subarray of size k from a given array

Last update on March 18 2025 13:20:56 (UTC/GMT +8 hours)

94. Largest Element of Each Contiguous Subarray of Size k

Write a program in C to find the largest element of each and every contiguous subarray of size k from a given array.

Expected Output:
The given array is:
1 3 6 21 4 9 12 3 16 10
The length of each subarray is: 4
The contigious subarray of length 4 and their maximum value are:
1 3 6 21 ----> 21
3 6 21 4 ----> 21
6 21 4 9 ----> 21
21 4 9 12 ----> 21
4 9 12 3 ----> 12
9 12 3 16 ----> 16
12 3 16 10 ----> 16

The task is to write a C program that finds the largest element in each contiguous subarray of size k from a given array. The program should iterate through the array, form subarrays of the specified size, and determine the maximum value in each subarray. The output should display each subarray along with its maximum value.

Sample Solution:

C Code:

#include<stdio.h>

// Function to print the subarray from index x to x+(k-1)
void contSubArr(int arr1[], int x, int k) 
{ 
    for (int i = x; i <= x + (k - 1); i++) 
    { 
        printf("%d ", arr1[i]); // Print the elements of the subarray
    } 
}

// Function to find the maximum in each subarray of length k
void findMaxFrom(int arr1[], int n, int k) 
{ 
    int j, maxofn, m = 0; 
    for (int i = 0; i <= n - k; i++) // Loop through the array from start to n-k
    { 
        maxofn = arr1[i]; // Set the first element of subarray as the initial maximum

        for (j = 1; j < k; j++) // Loop within the subarray
        { 
            if (arr1[i + j] > maxofn) // Update maximum if a larger element is found
               maxofn = arr1[i + j]; 
        } 
        contSubArr(arr1, m, k); // Print the subarray
        printf("----> %d \n", maxofn); // Print the maximum value of the subarray
        m++; // Move to the next subarray
    } 
}  

int main() 
{ 
    int arr1[] = {1, 3, 6, 21, 4, 9, 12, 3, 16, 10}; 
    int n = sizeof(arr1) / sizeof(arr1[0]); 
    int i, k = 4; 

    //------------- print original array ------------------	
    printf("The given array is:  \n");
    for (i = 0; i < n; i++)
    {
        printf("%d  ", arr1[i]); // Print the original array
    }
    printf("\n");
    //-----------------------------------------------------------

    printf("The length of each subarray is: %d\n", k);
    printf("The contiguous subarrays of length %d and their maximum value are: \n", k);
    findMaxFrom(arr1, n, k); // Find and print max in subarrays of length k

    return 0; 
}

Output:

The given array is:  
1  3  6  21  4  9  12  3  16  10  
The length of each subarray is: 4
The contigious subarray of length 4 and their maximum value are: 
1 3 6 21 ----> 21 
3 6 21 4 ----> 21 
6 21 4 9 ----> 21 
21 4 9 12 ----> 21 
4 9 12 3 ----> 12 
9 12 3 16 ----> 16 
12 3 16 10 ----> 16

Visual Presentation:

Flowchart:/p>

For more Practice: Solve these Related Problems:

• Write a C program to compute the maximum of each contiguous subarray of size k using a deque for efficiency.
• Write a C program to find the maximum element in each subarray of size k using nested loops and then optimize it.
• Write a C program to determine the maximum for every subarray of size k using dynamic programming.
• Write a C program to display each subarray of size k along with its maximum element using the sliding window technique.

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