結果
問題 | No.144 エラトステネスのざる |
ユーザー |
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提出日時 | 2017-01-07 08:25:20 |
言語 | C++14 (gcc 13.3.0 + boost 1.87.0) |
結果 |
AC
|
実行時間 | 3 ms / 2,000 ms |
コード長 | 2,398 bytes |
コンパイル時間 | 1,257 ms |
コンパイル使用メモリ | 100,724 KB |
実行使用メモリ | 6,820 KB |
最終ジャッジ日時 | 2024-12-17 15:19:52 |
合計ジャッジ時間 | 2,051 ms |
ジャッジサーバーID (参考情報) |
judge3 / judge2 |
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ファイルパターン | 結果 |
---|---|
sample | AC * 3 |
other | AC * 17 |
ソースコード
#pragma GCC optimize ("O3")#pragma GCC target ("avx")#include <cstdio>#include <cassert>#include <cmath>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <map>#include <set>#include <functional>#include <stack>#include <queue>#include <tuple>#define getchar getchar_unlocked#define putchar putchar_unlocked#define _rep(_1, _2, _3, _4, name, ...) name#define rep2(i, n) rep3(i, 0, n)#define rep3(i, a, b) rep4(i, a, b, 1)#define rep4(i, a, b, c) for (int i = int(a); i < int(b); i += int(c))#define rep(...) _rep(__VA_ARGS__, rep4, rep3, rep2, _)(__VA_ARGS__)using namespace std;using i8 = signed char;using i16 = signed short;using i64 = long long;using u8 = unsigned char;using u32 = unsigned;using u64 = unsigned long long;using f80 = long double;void solve() {const int N_MAX = 1e9;constexpr int sqrt_N = sqrt(N_MAX);static int smalls[sqrt_N + 1], larges[sqrt_N + 1];static int primes[sqrt_N + 1];int N;while (~scanf("%d", &N)) {double p; scanf("%lf", &p);int v = sqrt(N);rep(i, 1, v + 1) smalls[i] = i - 1, larges[i] = N / i - 1;rep(p, 2, v + 1) if (smalls[p] > smalls[p - 1]) {int q = p * p, pcnt = smalls[p - 1];rep(i, 1, min(N / q, v) + 1) {int d = i * p;larges[i] -= ((d <= v) ? larges[d] : smalls[N / d]) - pcnt;}for (int i = v; i >= q; --i) smalls[i] -= smalls[i / p] - pcnt;}int prime_size = 0;rep(i, 2, v + 1) if (smalls[i] > smalls[i - 1]) {primes[prime_size++] = i;}primes[prime_size++] = v + 1;static double pows[2000] = {1};rep(i, 1, 2000) pows[i] = pows[i - 1] * (1 - p);function< double(int, int, int) > rec = [&] (int n, int pi, int d) {double ret = 0.0;int t = ((n > v) ? larges[N / n] : smalls[n]) - smalls[primes[pi] - 1];ret += pows[2 * (d - 1)] * t;rep(pj, pi, prime_size) {int pr = primes[pj];if (pr * pr > n) break;for (int q = pr, nd = d * 2; i64(q) * pr <= n; q *= pr) {ret += rec(n / q, pj + 1, nd);nd += d;ret += pows[nd - 2];}}return ret;};double ans = rec(N, 0, 1);printf("%.12f\n", ans);}}int main() {auto beg = clock();solve();auto end = clock();fprintf(stderr, "%.3f sec\n", double(end - beg) / CLOCKS_PER_SEC);}