Here's an implementation that works -- any ideas on how to make it go faster? public static void divide_without_slash_or_mod(int num, int divisor) { int factor = 0; int remainder = num; System.out.println("Number = " + num + " divisor = " + divisor); while(remainder >= divisor) { remainder -= divisor; factor++; } System.out.println(" remainder = " + remainder + " factor = " + factor ); }

Here is the Java implementation of implementing division with O(log n) time complexity (actually, this solution is using divide operator). public static void divide(int dividend, int divisor) { int mid, low = 0, high = Integer.MAX_VALUE / divisor; while(low dividend) { high = mid-1; } else { low = mid +1; } } }

Binary search

D(Divisor), N(Divident) low = 0, high = INT_MAX/D while(low N) high = mid - 1; else low = mid + 1; } return -1; //No divisor

Optimal running time: O(log n)