3944: Sum
Time Limit: 10 Sec Memory Limit: 128 MBDescription
Input
一共T+1行
第1行为数据组数T(T<=10)
第2~T+1行每行一个非负整数N,代表一组询问
Output
一共T行,每行两个用空格分隔的数ans1,ans2
Sample Input
6
1
2
8
13
30
2333
1
2
8
13
30
2333
Sample Output
1 1
2 0
22 -2
58 -3
278 -3
1655470 2
2 0
22 -2
58 -3
278 -3
1655470 2
杜教筛入门
其实就是通过
[ sumlimits_{i=1}^nsumlimits_{d|i}mu(d) = 1 ]
[ sumlimits_{i=1}^nsumlimits_{j=1}^{leftlfloorfrac{n}{i}
ight
floor}mu(j) = 1 ]
[ sumlimits_{i=1}^nmu(i) = 1-sumlimits_{i=2}^nsumlimits_{j=1}^{leftlfloorfrac{n}{i}
ight
floor}mu(j) ]
然后预处理前( n ^ {frac{2}{3}} )个函数值,询问时递归处理。
1 #include<bits/stdc++.h> 2 using namespace std; 3 template <class _T> inline void read(_T &_x) { 4 int _t; bool flag = false; 5 while ((_t = getchar()) != '-' && (_t < '0' || _t > '9')) ; 6 if (_t == '-') _t = getchar(), flag = true; _x = _t - '0'; 7 while ((_t = getchar()) >= '0' && _t <= '9') _x = _x * 10 + _t - '0'; 8 if (flag) _x = -_x; 9 } 10 typedef long long LL; 11 const int maxn = 5000000; 12 LL phi[maxn], mu[maxn]; 13 int prime[maxn / 10], pcnt; 14 bool vis[maxn]; 15 inline void init() { 16 phi[0] = mu[0] = 0; 17 phi[1] = mu[1] = 1; 18 for (int i = 2; i < maxn; ++i) { 19 if (!vis[i]) { 20 prime[++pcnt] = i; 21 mu[i] = -1, phi[i] = i - 1; 22 } 23 for (LL j = 1, tmp; j <= pcnt && (tmp = prime[j] * i) < maxn; ++j) { 24 vis[tmp] = true; 25 if (i % prime[j] == 0) { 26 phi[tmp] = phi[i] * prime[j]; 27 mu[tmp] = 0; 28 break; 29 } 30 phi[tmp] = phi[i] * (prime[j] - 1); 31 mu[tmp] = -mu[i]; 32 } 33 } 34 for (int i = 2; i < maxn; ++i) phi[i] += phi[i - 1], mu[i] += mu[i - 1]; 35 } 36 map<LL, LL> Mphi, Mmu; 37 LL Phi(LL n) { 38 if (n < maxn) return phi[n]; 39 if (Mphi.find(n) != Mphi.end()) return Mphi[n]; 40 LL ret = ((LL)n * (n + 1)) >> 1; 41 for (LL i = 2, j, t; i <= n; i = j + 1) { 42 t = n / i, j = n / t; 43 ret -= (j - i + 1) * Phi(t); 44 } 45 Mphi[n] = ret; 46 return ret; 47 } 48 LL Mu(LL n) { 49 if (n < maxn) return mu[n]; 50 if (Mmu.find(n) != Mmu.end()) return Mmu[n]; 51 LL ret = 1; 52 for (LL i = 2, j, t; i <= n; i = j + 1) { 53 t = n / i, j = n / t; 54 ret -= (j - i + 1) * Mu(t); 55 } 56 Mmu[n] = ret; 57 return ret; 58 } 59 int main() { 60 //freopen(); 61 //freopen(); 62 init(); 63 LL T, N; read(T); 64 while (T--) { 65 read(N); 66 printf("%lld %lld ", Phi(N), Mu(N)); 67 } 68 return 0; 69 }