제출 #637642

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
637642		dxz05	건물 4 (JOI20_building4)	C++14	0 / 100	0 ms	340 KiB

building4

//#pragma GCC optimize("Ofast,O2,O3,unroll-loops")
//#pragma GCC target("avx2")

#include <bits/stdc++.h>

using namespace std;

void debug_out() { cerr << endl; }

template<typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
    cerr << "[" << H << "]";
    debug_out(T...);
}

#ifdef dddxxz
#define debug(...) cerr << "[" << #__VA_ARGS__ << "]:", debug_out(__VA_ARGS__)
#else
#define debug(...) 42
#endif

#define SZ(s) ((int)s.size())
#define all(x) (x).begin(), (x).end()
#define lla(x) (x).rbegin(), (x).rend()
#define bpc(x) __builtin_popcount(x)
#define bpcll(x) __builtin_popcountll(x)
#define MP make_pair

clock_t startTime;

int getCurrentTime() {
    return int((double) (clock() - startTime) / CLOCKS_PER_SEC * 1000);
}

mt19937 rng(chrono::high_resolution_clock::now().time_since_epoch().count());

typedef long long ll;
const int MOD = 998244353;
const int INF = 1000000101;
const long long LLINF = 1223372000000000555;
const int N = 1e6 + 3e2;

int a[N], b[N];
int dpl[N][2], pl[N][2];
int dpr[N][2], pr[N][2];

bool chmin(int &x, int y){
    if (x <= y) return false;
    x = y;
    return true;
}

bool chmax(int &x, int y){
    if (x >= y) return false;
    x = y;
    return true;
}

void solve(int TC) {
    int n;
    cin >> n;

    for (int i = 1; i <= 2 * n; i++) cin >> a[i];
    for (int i = 1; i <= 2 * n; i++) cin >> b[i];

    for (int i = 1; i <= 2 * n; i++){
        dpl[i][0] = dpl[i][1] = INF;
        dpr[i][0] = dpr[i][1] = -INF;
        pl[i][0] = pl[i][1] = -1;
        pr[i][0] = pr[i][1] = -1;
    }

    dpl[1][0] = 1;
    dpl[1][1] = 0;
    dpr[1][0] = 1;
    dpr[1][1] = 0;

    for (int i = 2; i <= 2 * n; i++){
        if (a[i] >= a[i - 1]){
            if (chmin(dpl[i][0], dpl[i - 1][0] + 1)) pl[i][0] = 0;
            if (chmax(dpr[i][0], dpr[i - 1][0] + 1)) pr[i][0] = 0;
        }
        if (a[i] >= b[i - 1]){
            if (chmin(dpl[i][0], dpl[i - 1][1] + 1)) pl[i][0] = 1;
            if (chmax(dpr[i][0], dpr[i - 1][1] + 1)) pr[i][0] = 1;
        }
        if (b[i] >= a[i - 1]){
            if (chmin(dpl[i][1], dpl[i - 1][0])) pl[i][1] = 0;
            if (chmax(dpr[i][1], dpr[i - 1][0])) pr[i][1] = 0;
        }
        if (b[i] >= b[i - 1]){
            if (chmin(dpl[i][1], dpl[i - 1][1])) pl[i][1] = 1;
            if (chmax(dpr[i][1], dpr[i - 1][1])) pr[i][1] = 1;
        }
    }

    int i = 2 * n;
    int x = -1;

    if (dpl[2 * n][0] <= n && n <= dpr[2 * n][0]) x = 0;
    if (dpl[2 * n][1] <= n && n <= dpr[2 * n][1]) x = 1;

    if (x == -1){
        cout << -1;
        return;
    }

    string s;

    if (x == 0){
        s += 'A';
        n--;
    } else {
        s += 'B';
    }

    while (i > 1){
        int y = pl[i][x];
        if (y == 0){
            s += 'A';
            n--;
        } else {
            s += 'B';
        }
        x = y;
        i--;
    }

    reverse(all(s));

    cout << s << endl;

}

int main() {
    startTime = clock();
    ios_base::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr);

#ifdef dddxxz
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
#endif

    int TC = 1;
    //cin >> TC;

    for (int test = 1; test <= TC; test++) {
        //debug(test);
        //cout << "Case #" << test << ": ";
        solve(test);
    }

#ifdef dddxxz
    cerr << endl << "Time: " << getCurrentTime() << " ms" << endl;
#endif

    return 0;
}

• Subtask 1: 0 / 11
• Subtask 2: 0 / 89