Javascript Program to Count of rotations required to generate a sorted array

<script>

// JavaScript program to find the
// count of rotations

// Function to return the count of
// rotations
function countRotation(arr, n)
{
    for(let i = 1; i < n; i++)
    {
        
        // Find the smallest element
        if (arr[i] < arr[i - 1])
        {
            
            // Return its index
            return i;
        }
    }
    
    // If array is not
    // rotated at all
    return 0;
}

// Driver Code
let arr1 = [ 4, 5, 1, 2, 3 ];

document.write(countRotation(
    arr1, arr1.length));
    
// This code is contributed by sanjoy_62

</script>

<script>
// Javascript Program to implement
// the above approach
 

// Function to return the
    // count of rotations
function countRotation(arr,low,high)
{

    // If array is not rotated
        if (low > high) {
            return 0;
        }
 
        let mid = low + Math.floor((high - low) / 2);
 
        // Check if current element is
        // greater than the next
        // element
 
        if (mid < high
            && arr[mid] > arr[mid + 1]) {
            // the next element is
            // the smallest
            return mid + 1;
        }
 
        // Check if current element is
        // smaller than it's previous
        // element
        if (mid > low
            && arr[mid] < arr[mid - 1]) {
            // Current element is
            // the smallest
            return mid;
        }
 
        // Check if current element is
        // greater than lower bound
 
        if (arr[mid] > arr[low]) {
            // The sequence is increasing
            // so far
            // Search for smallest
            // element on the right
            // subarray
            return countRotation(arr,
                                mid + 1,
                                high);
        }
 
        if (arr[mid] < arr[high])
        {
        
            // Smallest element lies on the
            // left subarray
            return countRotation(arr,
                                low,
                                mid - 1);
        }
 
        else
        {
        
            // Search for the smallest
            // element on both subarrays
            let rightIndex = countRotation(arr,
                                        mid + 1,
                                        high);
            let leftIndex = countRotation(arr,
                                        low,
                                        mid - 1);
 
            if (rightIndex == 0) {
                return leftIndex;
            }
 
            return rightIndex;
        }
}

 // Driver Program
let arr1=[4, 5, 1, 2, 3 ];
document.write(
            countRotation(
                arr1,
                0, arr1.length
                    - 1));

// This code is contributed by avanitrachhadiya2155
</script>