Leetcode

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Calculate the sum of two integers a and b, but you are not allowed to use the operator + and -.

Example:
Given a = 1 and b = 2, return 3.

// Iterative
public int getSum(int a, int b) {
	if (a == 0) return b;
	if (b == 0) return a;

	while (b != 0) {
		int carry = a & b;
		a = a ^ b;
		b = carry << 1;
	}
	
	return a;
}

// Iterative
public int getSubtract(int a, int b) {
	while (b != 0) {
		int borrow = (~a) & b;
		a = a ^ b;
		b = borrow << 1;
	}
	
	return a;
}

// Recursive
public int getSum(int a, int b) {
	return (b == 0) ? a : getSum(a ^ b, (a & b) << 1);
}

// Recursive
public int getSubtract(int a, int b) {
	return (b == 0) ? a : getSubtract(a ^ b, (~a & b) << 1);
}