Binary Search: Two implementations basically the same but only one works. Why?

This is the question

After getting stuck I tried typing it in java. It failed to work. Here is the code:

public static boolean run1(int data, int x)
if(data.length == 0)
return false;
else if (data.length ==1)
if(data[0]==x)
return true;
else return false;

else
int m = (data.length)/2;
if(x<=data[m])
int left = Arrays.copyOfRange(data, 0, m+1);
return run1(left,x);
else
int right = Arrays.copyOfRange(data, m+1, data.length);
return run1(right,x);






But after trying a bunch of things, I made a change that made it work for all cases.

public static boolean run(int data, int x)
if(data.length == 0)
return false;
else if (data.length ==1)
if(data[0]==x)
return true;
else return false;

else
int m = data.length/2;
if(x<data[m])
int left = Arrays.copyOfRange(data, 0, m);
return run(left,x);
else
int right = Arrays.copyOfRange(data, m, data.length);
return run(right,x);







Why would it work for the second one but not the first? they both are essentially doing the same thing?

I suspect it to be something with the Len(A)/2, The first how miraculously works perfectly when I change the division statement to (len(A) - 1)/2, kinda makes sense because Len(A) - 1 = 0 + Len(A) -1 (First index + last index)

Edit: im NOT asking for the answer to the question on the paper where I found this code. Just an answer to how the change I made to the code ended up making it work

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