Question

17.01. Add Without Plus

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Description

Write a function that adds two numbers. You should not use + or any arithmetic operators.

Example:

Input: a = 1, b = 1

Output: 2

 

Note:

• a and b may be 0 or negative.
• The result fits in 32-bit integer.

Solutions

Solution 1

class Solution {
  public int add(int a, int b) {
    int sum = 0, carry = 0;
    while (b != 0) {
      sum = a ^ b;
      carry = (a & b) << 1;
      a = sum;
      b = carry;
    }
    return a;
  }
}