Operations: Implement Multiply, Subtract, Divide Using Only Addition (CTCI 16.9)

The Problem: CTCI problem 16.9 technical mechanics.
The Approach: CTCI problem 16.9: write arithmetic operations (multiply, subtract, divide) for integers using only addition and bitwise ops.
Complexity: Optimal Time and Memory bounds.

TL;DR

The Problem: CTCI problem 16.9 technical mechanics.

The Approach: CTCI problem 16.9: write arithmetic operations (multiply, subtract, divide) for integers using only addition and bitwise ops.

Complexity: Optimal Time and Memory bounds.

This article provides a clear breakdown of CTCI problem 16.9.

1. Context and Problem Statement

CTCI problem 16.9: write arithmetic operations (multiply, subtract, divide) for integers using only addition and bitwise ops.

2. Technical Code & Mechanics

public static int minus(int a, int b) { return a + negate(b); }
private static int negate(int a) {
    int neg = 0;
    int d = a < 0 ? 1 : -1;
    while (a != 0) { neg += d; a += d; }
    return neg;
}

3. Key Takeaways and Edge Cases

Always test boundary conditions and invalid input states.