제출 #807639

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
807639		SorahISA	Cheerleaders (info1cup20_cheerleaders)	C++17	0 / 100	1802 ms	4212 KiB

cheerleaders

#ifndef SorahISA
#define SorahISA
#include SorahISA __FILE__ SorahISA

void solve() {
    int N, NN; cin >> N, NN = (1 << N);
    
    vector<int> A(NN), inv(NN);
    for (int i = 0; i < NN; ++i) cin >> A[i], inv[A[i]] = i;
    
    auto ch1 = [&](vector<int> &Z) {
        for (int i = 0; i < NN/2; ++i) swap(Z[i], Z[i+NN/2]);
        // cerr << "\u001b[34m";
        // for (int i = 0; i < NN; ++i) cerr << Z[i] << " \n"[i == NN-1];
        // cerr << "\u001b[0m";
    };
    
    auto ch2 = [&](vector<int> &Z) {
        static vector<int> B(NN);
        for (int i = 0; i < NN; i += 2) B[i/2] = Z[i];
        for (int i = 1; i < NN; i += 2) B[i/2+NN/2] = Z[i];
        Z = B;
        // cerr << "\u001b[35m";
        // for (int i = 0; i < NN; ++i) cerr << Z[i] << " \n"[i == NN-1];
        // cerr << "\u001b[0m";
    };
    
    auto calc_inv = [&](vector<int> &id) -> int64_t {
        static vector<int> BIT(NN+1);
        fill(ALL(BIT), 0);
        int64_t cnt = 0;
        for (int i = NN-1; i >= 0; --i) {
            for (int j = A[id[i]]+1; j >   0; j -= j&-j) cnt += BIT[j];
            for (int j = A[id[i]]+1; j <= NN; j += j&-j) ++BIT[j];
        }
        return cnt;
    };
    
    auto calc_cost = [&](vector<int> &id, int blk) -> bool {
        static vector<int> BIT(NN+1);
        fill(ALL(BIT), 0);
        int64_t cnt0 = 0, cnt1 = 0;
        for (int i = 0; i < NN; i += blk) {
            int tmp = 0;
            for (int j = 0; j < blk/2; ++j) {
                for (int k = A[id[i+j]]+1; k <= NN; k += k&-k) ++BIT[k];
            }
            for (int j = blk/2; j < blk; ++j) {
                for (int k = A[id[i+j]]+1; k >   0; k -= k&-k) tmp += BIT[k];
            }
            cnt0 += (blk/2) * (blk/2) - tmp, cnt1 += tmp;
        }
        return cnt1 < cnt0;
    };
    
    int64_t min_inv = NN * (NN-1) / 2;
    string min_ans;
    
    vector<int> id(NN); iota(ALL(id), 0);
    for (int op2 = 0; op2 < N; ++op2) {
        ch2(id);
        int C = 0;
        for (int bit = 0; bit < N; ++bit) {
            if (calc_cost(id, 1<<bit)) {
                C ^= (1 << bit);
                for (int &x : id) x ^= (1 << bit);
            }
        }
        
        string ans(op2, '2');
        for (int i = 0; i < N; ++i) {
            ans += "2", ch2(id);
            if (C >> i & 1) ans += "1", ch1(id);
        }
        for (int i = 0; i < N; ++i) {
            if (int64_t tmp = calc_inv(id); tmp < min_inv) min_inv = tmp, min_ans = ans;
            ans += "2", ch2(id);
        }
    }
    
    cout << min_inv << "\n";
    cout << min_ans << "\n";
}

int32_t main() {
    fastIO();
    
    int t = 1; // cin >> t;
    for (int _ = 1; _ <= t; ++_) {
        solve();
    }
    
    return 0;
}

#else

#ifdef local
#define _GLIBCXX_DEBUG 1
#endif
#pragma GCC optimize("Ofast", "unroll-loops")
#include <bits/stdc++.h>
using namespace std;

// #define int int64_t
// #define double __float80
using pii = pair<int, int>;
template <typename T> using Prior = std::priority_queue<T>;
template <typename T> using prior = std::priority_queue<T, vector<T>, greater<T>>;

// #define X first
// #define Y second
#define eb emplace_back
#define ef emplace_front
#define ee emplace
#define pb pop_back
#define pf pop_front
#define ALL(x) begin(x), end(x)
#define RALL(x) rbegin(x), rend(x)
#define SZ(x) ((int)(x).size())

#ifdef local
#define fastIO() void()
#define debug(...) \
    fprintf(stderr, "%sAt [%s], line %d: (%s) = ", "\u001b[33m", __FUNCTION__, __LINE__, #__VA_ARGS__), \
    _do(__VA_ARGS__), fprintf(stderr, "%s", "\u001b[0m")
template <typename T> void _do(T &&_t) {cerr << _t << "\n";}
template <typename T, typename ...U> void _do(T &&_t, U &&..._u) {cerr << _t << ", ", _do(_u...);}
#else
#define fastIO() ios_base::sync_with_stdio(0), cin.tie(0)
#define debug(...) void()
#endif

mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());

template <typename T, typename U> bool chmin(T &lhs, U rhs) {return lhs > rhs ? lhs = rhs, 1 : 0;}
template <typename T, typename U> bool chmax(T &lhs, U rhs) {return lhs < rhs ? lhs = rhs, 1 : 0;}

#endif

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• Subtask 2: 0 / 10
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• Subtask 4: 0 / 21
• Subtask 5: 0 / 28