void~~尴尬了，原来是卡速米打溢出了......锉......
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by DG_KONJ @ 2018-01-24 19:04:33
在LZ同一机房的我以帮助接决。
bug:快速幂中途溢出
```cpp
long long fast_pow(long long a,long long n){
if(!n)return 1;
if(n==1)return a;
long long sum=fast_pow(a,(n>>1))%mod;
if(n%2==1)return /*sum*sum*a%mod*/sum*sum%mod*a%mod;
else return sum*sum%mod;
}
```
by wycissilly @ 2018-01-24 19:05:31