Binary Search

1. Searching an Element in a Rotated Sorted Array

int r_binary_search(int arr[], int size, int key)
{
    int left = 0;
    int right = size - 1;
    int mid;

    while(left <= right)
    {
        mid = (left + right)/2;
        if(arr[mid] == key)
            return mid;

        if(arr[mid] >= arr[left])
        {
            if(key < arr[mid] && key >= arr[left])
                right = mid - 1;
            else
                left = mid + 1;
        }
        else
        {
            if(key > arr[mid] && key <= arr[right])
                left = mid + 1;
            else
                right = mid - 1;
        }
    }
    return -1;
}

2. fin min in a rotated array.

int find_min(int arr[], int size)
{
    int left = 0;
    int right = size - 1;
    int mid;

    while(left < right)
    {
        mid = (left + right)/2;
        
        if(arr[left] <= arr[right])
            return left;
        else if(arr[mid] >= arr[left])
            left = mid + 1;
        else
            right = mid;
    }
}