Randomized Match Finding

Question

Say I have two files or arrays, type doesn't matter, with a size of 184x184. I try to find out if these items are different with a code like below:

for(i=0; i<N; i++) {
    x = r.nextInt(184);
    y = r.nextInt(184);
    if(item1[x,y] != item2[x,y]) {
        break;
    }
}

My question is, what should the value of N be? Should I run tests, is there a defacto rate between N and the size?

Answer 1

As the program gets out of the loop when it finds differents values for the same index:

• It's OK to give N a big number, the loop won't tire the computer as the loop will be broken in at most 10th-20th step.

As differences will be found in very low values of "i":

• There's no need for bigger values of N.

So according to my experimentations, defacto value for N is 20. For similar or background is dominant in the pictures the value can be increased up to 100.