# Pow(x, n)

Implement `pow(x, n)`

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You don’t need to care about the precision of your answer, it’s acceptable if the expected answer and your answer ‘s difference is smaller than `1e-3`

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Example

```
x n pow(x, n)
2.1 3 9.261
0 1 0
1 0 1
```

The following implements the exponentiation by squaring algorithm, which is described here.