72 lines
1.2 KiB
C++
72 lines
1.2 KiB
C++
#include <bits/stdc++.h> // {{{
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// https://codeforces.com/blog/entry/96344
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#pragma GCC optimize("O2,unroll-loops")
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#pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt")
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using namespace std;
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template <typename T>
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constexpr T MIN = std::numeric_limits<T>::min();
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template <typename T>
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constexpr T MAX = std::numeric_limits<T>::max();
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template <typename T>
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[[nodiscard]] static T sc(auto &&x) {
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return static_cast<T>(x);
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}
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template <typename T>
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[[nodiscard]] static T sz(auto &&x) {
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return static_cast<T>(x.size());
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}
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using ll = long long;
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using ld = long double;
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template <typename T>
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using vec = std::vector<T>;
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template <typename T, size_t N>
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using arr = std::array<T, N>;
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#define ff first
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#define ss second
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#define eb emplace_back
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#define pb push_back
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#define all(x) (x).begin(), (x).end()
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#define rall(x) (x).rbegin(), (x).rend()
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// }}}
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void solve() {
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int n;
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cin >> n;
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/*
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every time 10 goes into it, + 1
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1 * 2 * 3 * 4 * 5 <- 1
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6 * 7 * 8 * 9 * 10
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11 12 13 14 15
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16 17 18 19 20
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*/
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int ans = 0;
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int b = 5;
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while (n / b) {
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ans += n / b;
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b *= 5;
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}
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cout << ans << endl;
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}
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int main() { // {{{
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cin.tie(nullptr)->sync_with_stdio(false);
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solve();
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return 0;
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}
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// }}}
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