Jerry's trouble
Problem's Link: http://acm.csu.edu.cn/OnlineJudge/problem.php?id=1556
Mean:
略。
analyse:
水题，直接快速幂。
Time complexity: O(n)
Source code:
// Memory Time // 1347K 0MS // by : crazyacking // 2015-03-29-19.18 #include<map> #include<queue> #include<stack> #include<cmath> #include<cstdio> #include<vector> #include<string> #include<cstdlib> #include<cstring> #include<climits> #include<iostream> #include<algorithm> #define MAXN 1000010 #define LL long long using namespace std; const LL MOD=1e9+7; LL quick_pow(LL a,LL b,LL m) { LL ans=1; while(b) { if(b&1) { ans*=a; ans%=m; } a*=a; a%=m; b/=2; } return ans%m; } int main() { ios_base::sync_with_stdio(false); cin.tie(0); // freopen("C:\\Users\\Devin\\Desktop\\cin.cpp","r",stdin); // freopen("C:\\Users\\Devin\\Desktop\\cout.cpp","w",stdout); LL n,m; while(cin>>n>>m) { LL sum=0; for(int i=1;i<=n;++i) { sum+=quick_pow(i,m,MOD); sum%=MOD; } cout<<sum%MOD<<endl; } return 0; } /* */ /************************************************************** Problem: 1556 User: crazyacking Language: C++ Result: Accepted Time:2704 ms Memory:1476 kb ****************************************************************/
