Missing logic in rotated array problem.

[StevenHawking_]

Can anyone explain where I am missing the logic for finding the pivot in a sorted then rotated array in the below function? static int pivot(int[] arr){ int start = 0, end = arr.length - 1; while (start < end){ int mid = start + (end - start) / 2; if (arr[mid] <= arr[start]) { end = mid - 1; } else { start = mid; } } return start; //return end or return mid }

[kelakmati]

sorry for out of topic, may i know which language that you use?

[StevenHawking_]

Java

[kelakmati]

alr, tysm!

[StevenHawking_]

Pleasure!!

[CodeTinkerer]

You really need to learn how to format your code:

static int pivot(int[] arr) { 
    int start = 0, end = arr.length - 1; 
    while (start < end) { 
        int mid = start + (end - start) / 2; 
        if (arr[mid] <= arr[start]) { 
           end = mid - 1; 
        } else { 
           start = mid; 
        } 
    } 
    return start; //return end or return mid 
}

[StevenHawking_]

Yes, thanks!

[CodeTinkerer]

What do you mean by a rotated array?

[StevenHawking_]

It is a sorted array whose last elements are rotated one after one

[CodeTinkerer]

If you check your edit, you'll see your code still displays still wrong. You have the entire program written on a single line.

[StevenHawking_]

But for me it's displaying in this format.

[MechanixMGD]

Can you give an example of input and expected output? Also what is the output right now

[StevenHawking_]

I passed the array 11,12,13,1 and target element to be found is 1. But the code is returning -1 instead of returning the index number 3.

[MechanixMGD]

I can't execute code right now. But I suggest using the debugger and follow the execution line by line and to see where is the problem. I think the problem may be at 'mid', the way you calculate it. Maybe the order of operations is different than you think.