相等序列

相等序列

1E5以内的质数有 1E4个
每个质数跑1E5次，TLE

#include <bits/stdc++.h>

using i64 = long long;

std::vector<int> minp, primes;

void sieve(int n) {
    minp.assign(n + 1, 0);
    primes.clear();
    
    for (int i = 2; i <= n; i++) {
        if (minp[i] == 0) {
            minp[i] = i;
            primes.push_back(i);
        }
        
        for (auto p : primes) {
            if (i * p > n) {
                break;
            }
            minp[i * p] = p;
            if (p == minp[i]) {
                break;
            }
        }
    }
}

int main() {
    std::ios::sync_with_stdio(false);
    std::cin.tie(nullptr);

    sieve(1E5 + 5);

    // std::cout << "primes = " << primes.size() << "\n";
    // primes = 9593

    int n;
    std::cin >> n;

    std::vector<int> a(n);
    std::set<int> st;
    for (int i = 0; i < n; ++i) {
        std::cin >> a[i];
        for (int x = a[i]; x != 1; x /= minp[x]) {
            st.insert(minp[x]);
        }
    }

    int ans = 0;
    for (int p : primes) {
        std::vector<int> cnt(20);
        for (int i = 0; i < n; ++i) {
            int t = 0;
            for (int x = a[i]; x % p == 0; x /= p) {
                ++t;
            }
            cnt[t] += 1;
        }
        for (int i = 0, s = 0; i < 20; ++i) {
            s += cnt[i];
            ans += std::min(s, n - s);
        }
    }
    std::cout << ans;
}
```C++