104 lines
2 KiB
C++
104 lines
2 KiB
C++
#include <bits/stdc++.h> // {{{
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#include <version>
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#ifdef __cpp_lib_ranges_enumerate
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#include <ranges>
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namespace rv = std::views;
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namespace rs = std::ranges;
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#endif
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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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using i16 = int16_t;
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using u16 = uint16_t;
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using i32 = int32_t;
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using u32 = uint32_t;
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using i64 = int64_t;
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using u64 = uint64_t;
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using f64 = double;
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using f128 = long double;
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#if __cplusplus >= 202002L
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template <typename T> constexpr T MIN = std::numeric_limits<T>::min();
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template <typename T> constexpr T MAX = std::numeric_limits<T>::max();
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#endif
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#ifdef LOCAL
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#define db(...) std::print(__VA_ARGS__)
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#define dbln(...) std::println(__VA_ARGS__)
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#else
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#define db(...)
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#define dbln(...)
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#endif
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// }}}
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void solve() {
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u32 n;
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cin >> n;
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vector<u32> a(n);
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for (auto &e : a)
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cin >> e;
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auto f = [&](auto &&self, i32 l, i32 r) -> i64 {
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if (l + 1 == r) {
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return 0;
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}
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i32 m = l + (r - l) / 2;
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i64 left = self(self, l, m);
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i64 right = self(self, m, r);
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if (left == -1 || right == -1) {
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return -1;
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}
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bool oknoswap = true;
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for (i32 i = l; i < r - 1; ++i) {
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oknoswap = oknoswap && (a[i] < a[i + 1]);
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}
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if (oknoswap) {
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return left + right;
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}
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bool okswap = true;
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for (i32 i = m, cnt = 0; cnt < r - l - 1; ++cnt) {
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i32 nxt = i == r - 1 ? l : i + 1;
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okswap = okswap && (a[i] < a[nxt]);
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i = nxt;
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}
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if (okswap) {
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for (i32 i = 0; i < m - l; ++i) {
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swap(a[l + i], a[m + i]);
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}
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return left + right + 1;
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}
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return -1;
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};
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cout << f(f, 0, n) << '\n';
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}
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int main() { // {{{
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std::cin.exceptions(std::cin.failbit);
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#ifdef LOCAL
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std::cerr.rdbuf(std::cout.rdbuf());
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std::cout.setf(std::ios::unitbuf);
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std::cerr.setf(std::ios::unitbuf);
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#else
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std::cin.tie(nullptr)->sync_with_stdio(false);
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#endif
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u32 tc = 1;
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std::cin >> tc;
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for (u32 t = 0; t < tc; ++t) {
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solve();
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}
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return 0;
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}
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// }}}
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