Minimum Element In A Sorted And Rotated Array Problem Statement

Find the minimum element in an array that has been sorted in ascending order and rotated by an unknown pivot.

Example

{
"arr": [4, 5, 6, 7, 8, 1, 2, 3]
}

Output:

1

The array is sorted in the ascending order and right rotated by pivot 5. The minimum value 1 is at index 5.

Notes

Constraints:

• 1 <= number of array elements <= 10⁵
• -10⁹ <= any array element <= 10⁹
• Array elements are unique.

Code For Minimum Element In A Sorted And Rotated Array Solution: Binary Search

/*
Asymptotic complexity in terms of the size of the input list `n`:
* Time: O(log n).
* Auxiliary space: O(1).
* Total space: O(n).
*/

int find_minimum(vector<int> &arr) {
    if (arr.size() == 1) {
        return arr[0];
    }

    int left = 0, right = arr.size() - 1;
    if (arr[right] > arr[0]) {
        return arr[0];
    }

    // Binary search.
    while (right >= left) {
        int mid = left + (right - left) / 2;
        if (arr[mid] > arr[mid + 1]) {
            return arr[mid + 1];
        }
        if (arr[mid - 1] > arr[mid]) {
            return arr[mid];
        }
        if (arr[mid] > arr[0]) {
            left = mid + 1;
        }
        else {
            right = mid - 1;
        }
    }
    return -1;
}

We hope that these solutions to find minimum in rotated sorted array problem have helped you level up your coding skills. You can expect problems like these at top tech companies like Amazon and Google.

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