## 常數優化

```cpp linenums="1"
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
```

- <https://codeforces.com/blog/entry/96344>

## 卡常

- mod 

- 把 `#define int long long` 去掉