81 lines
1.4 KiB
C++
81 lines
1.4 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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string s;
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cin >> s;
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unordered_map<char, int> m;
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for (auto c : s)
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++m[c];
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int odd = 0;
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string ans(s.size(), 'A');
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int l = 0;
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for (auto& [k, v] : m) {
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if (v & 1) {
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if (++odd == 2) {
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cout << "NO SOLUTION";
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return;
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}
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ans[ans.size() / 2] = k;
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--v;
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}
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while (v) {
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ans[l++] = k;
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ans[ans.size() - l] = k;
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v -= 2;
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}
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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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