제출 #1363357

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1363357		retarde	건물 4 (JOI20_building4)	C++20	11 / 100	28 ms	8196 KiB

building4

#include <bits/stdc++.h>
using namespace std;

#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define int long long
#define all(x) (x).begin(), (x).end()

typedef long double ld;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;
typedef vector<vector<ll>> vvll;
typedef vector<string> vs;
typedef vector<vector<string>> vvs;
typedef vector<char> vc;
typedef vector<vector<char>> vvc;
typedef map<int, int> mii;
typedef unordered_map<int, int> umii;

const int mod = 1e9 + 7;
const int inf = INTMAX_MAX;
const bool tc = false;

int n; // ACTUAL IS 2*n
const int mxn = 5e5 + 5;
int arr[mxn][2]; 
int L[mxn][2], R[mxn][2];

inline void solve() {
    cin >> n;
    for (int i = 1; i <= 2*n; i++) cin >> arr[i][1];
    for (int i = 1; i <= 2*n; i++) cin >> arr[i][0];
    for (int i = 0; i <= 2*n; i++) {
        L[i][0] = L[i][1] = 1e18;
        R[i][0] = R[i][1] = -1e18;
    }
    L[1][1] = R[1][1] = 1;
    L[1][0] = R[1][0] = 0;

    for (int i = 2; i <= 2 * n; i++) {
        for (int p = 0; p < 2; p++) {
            for (int q = 0; q < 2; q++) {
                if (arr[i][p] >= arr[i - 1][q]) {
                    L[i][p] = min(L[i][p], L[i - 1][q] + p);
                    R[i][p] = max(R[i][p], R[i - 1][q] + p);
                }
            }
        }
    }

    auto good = [&](int i, int p, int x=n) {
        return (L[i][p] <= x && x <= R[i][p]);
    };

    if (!good(2*n,0) && !good(2*n,1)) {
        cout << "-1\n";
        return;
    }

    int ind = 2*n;
    int need = n;
    int cur = 0; if (good(2*n,1)) cur = 1;
    string ans = "";
    while (ind>0) {
        ans += "BA"[cur];
        need -= cur;
        if (ind==1) break;
        int p = -1;
        for (int pr = 0; pr < 2; pr++) {
            if (arr[ind - 1][pr] <= arr[ind][cur] && good(ind - 1, pr, need)) {
                p = pr;
                break;
            }
        }
        ind--;
        cur = p;
    }
    reverse(all(ans)); cout << ans << '\n';
}

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

signed main() {
    ios::sync_with_stdio(false);
    cout.tie(0);
    cin.tie(0);
    //setIO();

    int t = 1;
    if (tc) {
        cin >> t;
    }

    while (t--) {
        solve();
    }
}

컴파일 시 표준 에러 (stderr) 메시지

building4.cpp: In function 'void setIO(std::string)':
building4.cpp:91:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   91 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
building4.cpp:92:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   92 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• 서브태스크 1: 11 / 11
• 서브태스크 2: 0 / 89