Codeforces 915G Coprime Arrays 莫比乌斯反演 (看题解)
作者:互联网
啊,我感觉我更本不会莫比乌斯啊啊啊, 感觉每次都学不会, 我好菜啊。
#include<bits/stdc++.h> #define LL long long #define fi first #define se second #define mk make_pair #define PLL pair<LL, LL> #define PLI pair<LL, int> #define PII pair<int, int> #define SZ(x) ((int)x.size()) #define ull unsigned long long using namespace std; const int N = 2e6 + 7; const int inf = 0x3f3f3f3f; const LL INF = 0x3f3f3f3f3f3f3f3f; const int mod = 1000000007; const double eps = 1e-6; const double PI = acos(-1); int n, k, miu[N], Pown[N], sum[N]; int Power(int a, int b) { int ans = 1; while(b) { if(b & 1) ans = 1LL * ans * a % mod; a = 1LL * a * a % mod; b >>= 1; } return ans; } int main() { miu[1] = 1; for(int i = 1; i < N; i++) for(int j = i + i; j < N; j += i) miu[j] -= miu[i]; scanf("%d%d", &n, &k); for(int i = 1; i <= k; i++) Pown[i] = Power(i, n); int ans = 0, tmp = 0; for(int i = 1; i <= k; i++) { for(int j = i; j <= k; j += i) { sum[j] = ((sum[j] + 1LL * miu[i] * (Pown[j / i] - Pown[j / i - 1])) % mod + mod) % mod; } tmp = (tmp + sum[i]) % mod; ans = (ans + (tmp ^ i)) % mod; } printf("%d\n", ans); return 0; } /* */
标签:const,Arrays,题解,Codeforces,long,int,ans,miu,define 来源: https://www.cnblogs.com/CJLHY/p/10570014.html