This website contains ALL LeetCode **Premium** problems for
**FREE!!**.

All leaked interview problems are collected from Internet.

All leaked interview problems are collected from Internet.

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.

**Credits:**

Special thanks to @fujiaozhu for adding this problem and creating all test cases.

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