# 461. Hamming Distance

The [Hamming distance](https://en.wikipedia.org/wiki/Hamming_distance) between two integers is the number of positions at which the corresponding bits are different.

Given two integers `x` and `y`, calculate the Hamming distance.

**Note:**\
0 ≤ `x`, `y` < 231.

**Example:**

```
Input: x = 1, y = 4

Output: 2

Explanation:
1   (0 0 0 1)
4   (0 1 0 0)
       ↑   ↑

The above arrows point to positions where the corresponding bits are different.
```

```cpp
int hammingDistance(int x, int y) { // time: O(1); space: O(1)
    int res = 0, tmp = x ^ y;
    while (tmp) {
        if (tmp & 1) ++res;
        tmp >>= 1;
    }
    return res;
}
```

```cpp
int hammingDistance(int x, int y) { // time: O(1); space: O(1)
    int res = 0, n = x ^ y;
    while (n) {
        ++res;
        n &= (n - 1);
    }
    return res;
}
```