C Exercises: Find the next greater elements in a given unsorted array

C Array: Exercise-43 with Solution

Write a program in C to print the next greatest elements in a given unsorted array. Elements for which no superior element exists, consider the next greatest element as -1.

The task is to find the next greatest element for each element in an unsorted array. For each element, the program finds the nearest greater element on its right; if none exists, it assigns -1.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>

// Function to find the next larger element for each element in the array
void findNxtLrgElem(int *arr1, int arr1_size) {
    int nxtBgElem, i, j;
    for(i = 0; i < arr1_size; i++) {
        // Find the next bigger element for arr1[i]
        for (j = i + 1, nxtBgElem = -1; j < arr1_size; j++) {
            if (arr1[i] < arr1[j]) {
                nxtBgElem = arr1[j];
                break;
            }
        }
        printf("Next bigger element of %d in the array is:   %d\n", arr1[i], nxtBgElem);
    }
}

// Function to form an array with next bigger elements
void formBigElemArray(int *arr1, int arr1_size) {
    int nxtBgElem, i, j;
    for(i = 0; i < arr1_size; i++) {
        // Find the next bigger element for arr1[i]
        for (j = i + 1, nxtBgElem = -1; j < arr1_size; j++) {
            if (arr1[i] < arr1[j]) {
                nxtBgElem = arr1[j];
                break;
            }
        }
        printf("%d ", nxtBgElem);
    }
}

int main() {
    int i, arr1[] = {5, 3, 10, 9, 6, 13};
    int ctr = sizeof(arr1) / sizeof(arr1[0]);

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

    // Find and print the next bigger elements for each element in the array
    printf("\nNext Bigger Elements are:\n");
    findNxtLrgElem(arr1, ctr);

    // Form and print an array with next bigger elements
    printf("\nNext Bigger Elements Array:\n");
    formBigElemArray(arr1, ctr);

    return 0;
}

Sample Output:

The given array is :  5  3  10  9  6  13  

Next Bigger Elements are:
Next bigger element of 5 in the array is:   10
Next bigger element of 3 in the array is:   10
Next bigger element of 10 in the array is:   13
Next bigger element of 9 in the array is:   13
Next bigger element of 6 in the array is:   13
Next bigger element of 13 in the array is:   -1

Next Bigger Elements Array:
10 10 13 13 13 -1 

Flowchart:

C Programming Code Editor:

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