# 476. Number Complement

## Easy

***

The **complement** of an integer is the integer you get when you flip all the `0`'s to `1`'s and all the `1`'s to `0`'s in its binary representation.

* For example, The integer `5` is `"101"` in binary and its **complement** is `"010"` which is the integer `2`.

Given an integer `num`, return *its complement*.

**Example 1:**

```
Input: num = 5
Output: 2
Explanation: The binary representation of 5 is 101 (no leading zero bits), and its complement is 010. So you need to output 2.
```

**Example 2:**

```
Input: num = 1
Output: 0
Explanation: The binary representation of 1 is 1 (no leading zero bits), and its complement is 0. So you need to output 0.
```

**Constraints:**

* `1 <= num < 231`

**Note:** This question is the same as 1009: <https://leetcode.com/problems/complement-of-base-10-integer/>

```python
class Solution:
    def findComplement(self, num: int) -> int:
        s = bin(num).replace('0b','')
        power = 0
        total = 0
        for char in s[::-1]:
            if char == '0':
                total += pow(2, power)
            power += 1
        return total
```