結果

問題 No.308 素数は通れません
ユーザー Yang33
提出日時 2018-09-30 17:03:02
言語 C++14
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 88 ms / 1,000 ms
コード長 3,454 bytes
コンパイル時間 1,713 ms
コンパイル使用メモリ 176,556 KB
実行使用メモリ 5,248 KB
最終ジャッジ日時 2024-10-12 09:13:10
合計ジャッジ時間 4,791 ms
ジャッジサーバーID
(参考情報)
judge3 / judge4
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ファイルパターン 結果
other AC * 107
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ソースコード

diff #
プレゼンテーションモードにする

#include <bits/stdc++.h>
using namespace std;
using VS = vector<string>; using LL = long long;
using VI = vector<int>; using VVI = vector<VI>;
using PII = pair<int, int>; using PLL = pair<LL, LL>;
using VL = vector<LL>; using VVL = vector<VL>;
#define ALL(a) begin((a)),end((a))
#define RALL(a) (a).rbegin(), (a).rend()
#define SZ(a) int((a).size())
#define SORT(c) sort(ALL((c)))
#define RSORT(c) sort(RALL((c)))
#define UNIQ(c) (c).erase(unique(ALL((c))), end((c)))
#define FOR(i, s, e) for (int(i) = (s); (i) < (e); (i)++)
#define FORR(i, s, e) for (int(i) = (s); (i) > (e); (i)--)
#define debug(x) cerr << #x << ": " << x << endl
const int INF = 1e9; const LL LINF = 1e16;
const LL MOD = 1000000007; const double PI = acos(-1.0);
int DX[8] = { 0, 0, 1, -1, 1, 1, -1, -1 }; int DY[8] = { 1, -1, 0, 0, 1, -1, 1, -1 };
/* ----- 2018/09/30 Problem: yukicoder 308 / Link: http://yukicoder.me/problems/no/308 ----- */
/* ------------
---------- */
/* ----------
-------- */
using LLL = __int128;
__int128 parse(string &s) {
__int128 ret = 0;
for (int i = 0; i < (int)s.length(); i++)
if (isdigit(s[i]))
ret = 10 * ret + s[i] - '0';
if (s[0] == '-')ret = -ret;
return ret;
}
std::istream &operator>>(std::istream &is, __int128 &value) {
string s; cin >> s;
value = parse(s);
return is;
}
vector<int> make_prime(LL N) {
vector<int> prime(N + 1, 1);
prime[0] = prime[1] = 0;
for (int i = 2; i <= N; i++) {
if (prime[i]) {
for (int j = i * 2; j <= N; j += i)
prime[j] = 0;
}
}
return prime;
}
LLL mul(const LLL a, const LLL b, const LLL mod) {
if (b == 0) { return 0; }
if (b % 2 == 1) {
return (mul(a, b - 1, mod) + a) % mod;
}
else {
const LLL pp = mul(a, b / 2, mod);
return (pp + pp) % mod;
}
}
LLL power(const LLL a, const LLL n, const LLL mod) {
if (n == 0) { return 1; }
if (n % 2 == 1) {
return mul(power(a, n - 1, mod), a, mod);
}
else {
const LLL aa = power(a, n / 2, mod);
return mul(aa, aa, mod);
}
}
int main() {
cin.tie(0);
ios_base::sync_with_stdio(false);
LLL N;
cin >> N;
int ans = 0;
if (N <= 1000) {
VI is_prime = make_prime(N + 1);
for (int w = 3; ; w++) {
VI masu(N + 1, 0);
masu[1] = 1;
queue<int>q;
q.push(1);
#define IN(a,b,c) (a<=b&&b<c)
vector<int> ds({ -w,w,-1,1 });
while (!q.empty()) {
int pos = q.front(); q.pop();
FOR(k, 0, 4) {
if (k == 3 && pos%w == 0)continue;
if (k == 2 && pos%w == 1)continue;
int nx = pos + ds[k];
if (IN(1, nx, N + 1) && !masu[nx] && !is_prime[nx]) {
masu[nx] = 1;
q.push(nx);
}
}
}
if (masu[N]) { ans = w; break; }
}
}
else {
auto f = [](LLL n) {
if (n == 1) { return 0; }
LLL s = 0, d = n - 1;
while (!(d & 1))s++, d >>= 1;
mt19937_64 rand_src(random_device{}());
FOR(i, 0, 100) {
const LLL a = (rand_src() % (n - 2)) + 1;
if (power(a, n - 1, n) != 1) { return 0; }
LLL num = power(a, d, n);
if (num != 1) {
bool comp = true;
FOR(_, 0, s) {
if (num == n - 1) {
comp = 0;
break;
}
num = mul(num, num, n);
}
if (comp) return 0;
}
}
return 1;
};
if (N % 8 == 1) {
// if N-8 prime : ans = 14
if (f(N - 8))ans = 14;
else ans = 8;
}
else {
ans = 8;
}
}
cout << ans << "\n";
return 0;
}
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