#1196119 (C++23) No.3783 Choose Disjoint Semicircles

• 問題: No.3783 Choose Disjoint Semicircles
• ユーザー: 👑 Forested
• 提出日時: 2026-10-30 22:48:58
• 言語: C++23 (gcc 15.3.0 + boost 1.92.0 + ACL)
• 結果: AC
• 実行時間: 501 ms / 2,000 ms
• コード長: 5,521 bytes
• コンパイル時間: 2,991 ms
• コンパイル使用メモリ: 353,648 KB
• 実行使用メモリ: 9,732 KB
• 平均クエリ数: 4493.62
• 最終ジャッジ日時: 2026-10-30 22:49:15
• 合計ジャッジ時間: 16,332 ms
• ジャッジサーバーID （参考情報）: judge1_0 / judge2_0

ファイルパターン	結果
sample	AC * 1
other	AC * 36

ソースコード

#ifndef LOCAL
#define FAST_IO
#endif

#define INT128

// ============
#include <bits/stdc++.h>
#define OVERRIDE(a, b, c, d, ...) d
#define REP2(i, n) for (i32 i = 0; i < (i32)(n); ++i)
#define REP3(i, m, n) for (i32 i = (i32)(m); i < (i32)(n); ++i)
#define REP(...) OVERRIDE(__VA_ARGS__, REP3, REP2)(__VA_ARGS__)
#define PER2(i, n) for (i32 i = (i32)(n)-1; i >= 0; --i)
#define PER3(i, m, n) for (i32 i = (i32)(n)-1; i >= (i32)(m); --i)
#define PER(...) OVERRIDE(__VA_ARGS__, PER3, PER2)(__VA_ARGS__)
#define ALL(x) begin(x), end(x)
#define LEN(x) (i32)(x.size())
using namespace std;
using u32 = unsigned int;
using u64 = unsigned long long;
using i32 = signed int;
using i64 = signed long long;
using f64 = double;
using f80 = long double;
using pi = pair<i32, i32>;
using pl = pair<i64, i64>;
template <typename T>
using V = vector<T>;
template <typename T>
using VV = V<V<T>>;
template <typename T>
using VVV = V<V<V<T>>>;
template <typename T>
using VVVV = V<V<V<V<T>>>>;
template <typename T>
using PQR = priority_queue<T, V<T>, greater<T>>;
template <typename T>
bool chmin(T &x, const T &y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
bool chmax(T &x, const T &y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}
template <typename T>
i32 lob(const V<T> &arr, const T &v) {
    return (i32)(lower_bound(ALL(arr), v) - arr.begin());
}
template <typename T>
i32 upb(const V<T> &arr, const T &v) {
    return (i32)(upper_bound(ALL(arr), v) - arr.begin());
}
template <typename T>
V<i32> argsort(const V<T> &arr) {
    V<i32> ret(arr.size());
    iota(ALL(ret), 0);
    sort(ALL(ret), [&](i32 i, i32 j) -> bool {
        if (arr[i] == arr[j]) {
            return i < j;
        } else {
            return arr[i] < arr[j];
        }
    });
    return ret;
}
#ifdef INT128
using u128 = __uint128_t;
using i128 = __int128_t;
#endif
[[maybe_unused]] constexpr i32 INF = 1000000100;
[[maybe_unused]] constexpr i64 INF64 = 3000000000000000100;
struct SetUpIO {
    SetUpIO() {
#ifdef FAST_IO
        ios::sync_with_stdio(false);
        cin.tie(nullptr);
#endif
        cout << fixed << setprecision(15);
    }
} set_up_io;
void scan(char &x) { cin >> x; }
void scan(u32 &x) { cin >> x; }
void scan(u64 &x) { cin >> x; }
void scan(i32 &x) { cin >> x; }
void scan(i64 &x) { cin >> x; }
void scan(f64 &x) { cin >> x; }
void scan(string &x) { cin >> x; }
template <typename T>
void scan(V<T> &x) {
    for (T &ele : x) {
        scan(ele);
    }
}
void read() {}
template <typename Head, typename... Tail>
void read(Head &head, Tail &...tail) {
    scan(head);
    read(tail...);
}
#define CHAR(...)     \
    char __VA_ARGS__; \
    read(__VA_ARGS__);
#define U32(...)     \
    u32 __VA_ARGS__; \
    read(__VA_ARGS__);
#define U64(...)     \
    u64 __VA_ARGS__; \
    read(__VA_ARGS__);
#define I32(...)     \
    i32 __VA_ARGS__; \
    read(__VA_ARGS__);
#define I64(...)     \
    i64 __VA_ARGS__; \
    read(__VA_ARGS__);
#define F64(...)     \
    f64 __VA_ARGS__; \
    read(__VA_ARGS__);
#define STR(...)        \
    string __VA_ARGS__; \
    read(__VA_ARGS__);
#define VEC(type, name, size) \
    V<type> name(size);       \
    read(name);
#define VVEC(type, name, size1, size2)    \
    VV<type> name(size1, V<type>(size2)); \
    read(name);
// ============

#ifdef DEBUGF
#else
#define DBG(...) (void)0
#endif

// ============
#include <chrono>
#include <random>

#if defined(LOCAL) || defined(FIX_SEED)
std::mt19937_64 mt(123456789);
#else
std::mt19937_64 mt(std::chrono::steady_clock::now().time_since_epoch().count());
#endif

template <typename T>
T uniform(T l, T r) {
    return std::uniform_int_distribution<T>(l, r - 1)(mt);
}
template <typename T>
T uniform(T n) {
    return std::uniform_int_distribution<T>(0, n - 1)(mt);
}
// ============

i32 get(const V<i32> &p, i32 i) {
    i %= LEN(p);
    if (i < 0) {
        i += LEN(p);
    }
    return p[i];
}

i32 f(V<i32> p) {
    i32 n = LEN(p);
    i32 mn = (i32)(min_element(ALL(p)) - begin(p));
    if (n % 4 == 0) {
        if (get(p, mn - 1) < get(p, mn + 1)) {
            mn = (mn + n - 1) % n;
        }
    }
    bool f1 = true, f2 = true;
    if (n % 4 == 0) {
        f1 = get(p, mn - 1) < get(p, mn + 2);
        f2 = get(p, mn + n / 2 - 1) < get(p, mn + n / 2 + 2);
    } else {
        f1 = get(p, mn - 1) < get(p, mn + 1);
        f2 = get(p, mn + n / 2 - 1) < get(p, mn + n / 2 + 1);
    }
    if (f1 == f2) {
        return (mn + n - (n - 1) / 4) % n;
    } else {
        return (mn + n + n / 2 - (n - 1) / 4) % n;
    }
}

bool test(V<i32> p, i32 r) {
    i32 n = LEN(p);
    i32 i1 = f(p);
    set<i32> x;
    REP(i, n / 2) {
        x.insert(get(p, i1 + i));
    }
    REP(i, n / 4) {
        i32 a = (i1 + i) % n;
        i32 b = (i1 + n / 2 - 1 - i) % n;
        swap(p[a], p[b]);
    }
    rotate(begin(p), begin(p) + r, end(p));
    i32 i2 = f(p);
    REP(i, n / 2) {
        if (x.contains(get(p, i2 + i))) {
            return false;
        }
    }
    return true;
}

void gen() {
    i32 n = uniform(3, 7) * 2;
    V<i32> p(n);
    iota(ALL(p), 0);
    shuffle(ALL(p), mt);
    i32 r = uniform(n);
    DBG(p, r);
    if (!test(p, r)) {
        cerr << "FAIL\n";
        exit(0);
    }
}
void test() {
    REP(iter, 100) {
        gen();
    }
    cerr << "OK\n";
}

void solve() {
    I32(n);
    VEC(i32, p, n);
    cout << f(p) << endl;
}

int main() {
    i32 t = 1;
    cin >> t;
    while (t--) {
        solve();
    }
}