結果

問題 No.864 四方演算
コンテスト
ユーザー hitonanode
提出日時 2019-08-16 21:26:06
言語 C++11（廃止可能性あり）
(gcc 13.3.0)
結果
AC  
実行時間 25 ms / 1,000 ms
コード長 4,991 bytes
コンパイル時間 1,686 ms
コンパイル使用メモリ 173,884 KB
実行使用メモリ 7,700 KB
最終ジャッジ日時 2024-09-25 10:42:02
合計ジャッジ時間 3,081 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge1
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 27
権限があれば一括ダウンロードができます

ソースコード

diff # 

#include <bits/stdc++.h>
using namespace std;
using lint = long long int;
using pint = pair<int, int>;
using plint = pair<lint, lint>;
struct fast_ios { fast_ios(){ cin.tie(0); ios::sync_with_stdio(false); cout << fixed << setprecision(20); }; } fast_ios_;
#define ALL(x) (x).begin(), (x).end()
#define SZ(x) ((lint)(x).size())
#define POW2(n) (1LL << (n))
#define FOR(i, begin, end) for(int i=(begin),i##_end_=(end);i<i##_end_;i++)
#define IFOR(i, begin, end) for(int i=(end)-1,i##_begin_=(begin);i>=i##_begin_;i--)
#define REP(i, n) FOR(i,0,n)
#define IREP(i, n) IFOR(i,0,n)
template<typename T> void ndarray(vector<T> &vec, int len) { vec.resize(len); }
template<typename T, typename... Args> void ndarray(vector<T> &vec, int len, Args... args) { vec.resize(len); for (auto &v : vec) ndarray(v, args...); }
template<typename T> bool mmax(T &m, const T q) { if (m < q) {m = q; return true;} else return false; }
template<typename T> bool mmin(T &m, const T q) { if (m > q) {m = q; return true;} else return false; }
template<typename T1, typename T2> pair<T1, T2> operator+(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first + r.first, l.second + r.second); }
template<typename T1, typename T2> pair<T1, T2> operator-(const pair<T1, T2> &l, const pair<T1, T2> &r) { return make_pair(l.first - r.first, l.second - r.second); }
template<typename T> istream &operator>>(istream &is, vector<T> &vec){ for (auto &v : vec) is >> v; return is; }
///// This part below is only for debug, not used /////
template<typename T> ostream &operator<<(ostream &os, const vector<T> &vec){ os << "["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const deque<T> &vec){ os << "deq["; for (auto v : vec) os << v << ","; os << "]"; return os; }
template<typename T> ostream &operator<<(ostream &os, const set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_set<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T> ostream &operator<<(ostream &os, const unordered_multiset<T> &vec){ os << "{"; for (auto v : vec) os << v << ","; os << "}"; return os; }
template<typename T1, typename T2> ostream &operator<<(ostream &os, const pair<T1, T2> &pa){ os << "(" << pa.first << "," << pa.second << ")"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
template<typename TK, typename TV> ostream &operator<<(ostream &os, const unordered_map<TK, TV> &mp){ os << "{"; for (auto v : mp) os << v.first << "=>" << v.second << ","; os << "}"; return os; }
#define dbg(x) cerr << #x << " = " << (x) << " (L" << __LINE__ << ") " << __FILE__ << endl;
///// END /////
/*
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/tag_and_trait.hpp>
using namespace __gnu_pbds; // find_by_order(), order_of_key()
template<typename TK> using pbds_set = tree<TK, null_type, less<TK>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename TK, typename TV> using pbds_map = tree<TK, TV, less<TK>, rb_tree_tag, tree_order_statistics_node_update>;
*/

vector<int> makePrimeLst(int N)
{
    vector<int> ans;
    vector<int> alive(N+1, 1);
    lint now = 2;
    for (; now * now <= N; now++)
    {
        if (alive[now]) ans.push_back(now);
        for (int t = now; t <= N; t += now) alive[t] = 0;
    }
    for (; now <= N; now++) if (alive[now]) ans.push_back(now);
    return ans;
}

// 素因数分解
map<lint, int> primeFactorize(lint N, const vector<int> &primeLst)
{
    map<lint, int> ans;
    for (auto v : primeLst)
    {
        while (!(N % v))
        {
            N /= v;
            ans[v]++;
        }
        if (N == 1) return ans;
    }
    ans[N]++;
    return ans;
    // exit(1);
}


// 約数 unsorted
vector<lint> divisor(lint n, const vector<int> &primeLst)
{
    map<lint, int> factor = primeFactorize(n, primeLst);
    vector<lint> now{1}, nxt;
    for (auto pa : factor)
    {
        nxt.clear();
        for (auto v : now)
        {
            REP(i, pa.second + 1)
            {
                nxt.push_back(v);
                v *= pa.first;
            }
        }
        swap(now, nxt);
    }
    return now;
}

lint solve(lint x, lint N)
{
    if (x > N * 2 or x < 2) return 0;
    if (x <= N + 1) return x - 1;
    return 2 * N + 1 - x;
}
int main()
{
    auto primes = makePrimeLst(1000000);
    lint N, K;
    cin >> N >> K;
    auto v = divisor(K, primes);
    lint ret = 0;
    for (auto x : v)
    {
        lint y = K / x;
        ret += solve(x, N) * solve(y, N);
    }
    cout << ret << endl;
}
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