C Exercises: Find minimum element in a sorted and rotated array

C Array: Exercise-57 with Solution

Write a program in C to find the minimum element in a sorted and rotated array.

Expected Output :
The given array is : 3 4 5 6 7 9 2
The minimum element in the above array is: 2

To find the minimum element in a sorted and rotated array, the program can use a modified binary search algorithm. This approach efficiently locates the minimum element by repeatedly dividing the array in half and comparing the middle element with the boundary elements to determine which subarray contains the minimum. This ensures an optimal time complexity of O(log n) for finding the minimum element.

Visual Presentation:

Sample Solution:

C Code:

#include <stdio.h>

// Function to find the minimum element in a rotated sorted array
int findMin(int arr1[], int start, int end) {
    // If the start index and end index are the same, return the element at that index
    if (start == end) {
        return arr1[start];
    }

    // Find the middle index
    int mid = (start + end) / 2;

    // If the element at the start index is greater than the element at the middle index,
    // the minimum element lies in the left half, so search in that half
    if (arr1[start] > arr1[mid]) {
        return findMin(arr1, start, mid);
    } else if (arr1[mid] > arr1[end]) {
        // If the element at the middle index is greater than the element at the end index,
        // the minimum element lies in the right half, so search in that half
        return findMin(arr1, mid + 1, end);
    } else {
        // If none of the conditions are met, the array is not rotated or only partially rotated,
        // so the minimum element is at the start index
        return arr1[start];
    }
}

int main() {
    int arr1[] = {3, 4, 5, 6, 7, 9, 2};
    int n = sizeof(arr1) / sizeof(arr1[0]);
    int i;

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

    // Find and print the minimum element in the rotated sorted array
    int min = findMin(arr1, 0, n - 1);
    printf("The minimum element in the above array is: %d\n", min);

    return 0;
}

Output:

The given array is :  3  4  5  6  7  9  2  
The minimum element in the above array is: 2 

Flowchart:

C Programming Code Editor:

Previous: Write a program in C to return the minimum number of jumps to reach the end of the array.
Next: Write a program in C to move all zeroes to the end of a given array.