Submission #402307

#	Time	Username	Problem	Language	Result	Execution time	Memory
402307		wiwiho	Building 4 (JOI20_building4)	C++14	100 / 100	292 ms	19440 KiB

building4

#include <bits/stdc++.h>
#include <bits/extc++.h>

#define StarBurstStream ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define iter(a) a.begin(), a.end()
#define riter(a) a.rbegin(), a.rend()
#define lsort(a) sort(iter(a))
#define gsort(a) sort(riter(a))
#define pb(a) push_back(a)
#define eb(a) emplace_back(a)
#define pf(a) push_front(a)
#define ef(a) emplace_front(a)
#define pob pop_back()
#define pof pop_front()
#define mp(a, b) make_pair(a, b)
#define F first
#define S second
#define mt make_tuple
#define gt(t, i) get<i>(t)
#define tomax(a, b) ((a) = max((a), (b)))
#define tomin(a, b) ((a) = min((a), (b)))
#define topos(a) ((a) = (((a) % MOD + MOD) % MOD))
#define uni(a) a.resize(unique(iter(a)) - a.begin())
#define printv(a, b) {bool pvaspace=false; \
for(auto pva : a){ \
    if(pvaspace) b << " "; pvaspace=true;\
    b << pva;\
}\
b << "\n";}

using namespace std;
using namespace __gnu_pbds;

typedef long long ll;
typedef unsigned long long ull;
typedef long double ld;

using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<ld, ld>;
using tiii = tuple<int, int, int>;

const ll MOD = 1000000007;
const ll MAX = 2147483647;

template<typename A, typename B>
ostream& operator<<(ostream& o, pair<A, B> p){
    return o << '(' << p.F << ',' << p.S << ')';
}

ll ifloor(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a < 0) return (a - b + 1) / b;
    else return a / b;
}

ll iceil(ll a, ll b){
    if(b < 0) a *= -1, b *= -1;
    if(a > 0) return (a + b - 1) / b;
    else return a / b;
}

int main(){
    StarBurstStream

    int n;
    cin >> n;

    vector<vector<int>> a(2, vector<int>(2 * n + 1));
    vector<int> c(2 * n + 1);
    for(int i = 1; i <= 2 * n; i++) cin >> a[0][i];
    for(int i = 1; i <= 2 * n; i++) cin >> a[1][i];

    int lst = 0;
    int t = 0;
    for(int i = 1; i <= 2 * n; i++){
        int mn = a[0][i] <= a[1][i] ? 0 : 1;
        if(lst <= a[mn][i]) c[i] = mn;
        else if(lst <= a[!mn][i]) c[i] = !mn;
        else{
            cout << "-1\n";
            return 0;
        }
        lst = a[c[i]][i];
        if(c[i] == 0) t++;
        else t--;
    }
//    printv(c, cerr);

    int rp = 2 * n, tmp = 0;
    bool no = false;
    for(int i = 2 * n; i >= 1 && t != 0; i--){
        if(a[c[i]][i] > a[!c[i]][i]){
            no = true;
            continue;
        }
        if(i < 2 * n && a[!c[i]][i] <= a[c[i + 1]][i + 1]){
            rp = i;
            tmp = 0;
            no = false;
        }
        else if(i < 2 * n && a[!c[i]][i] > a[!c[i + 1]][i + 1]){
            no = true;
        }

        if(no) continue;
        if(c[i] == 0) tmp -= 2;
        else tmp += 2;
//        cerr << "test " << i << " " << c[i] << " " << tmp << " " << t << " " << rp << "\n";

        if((ll)tmp * t >= 0) continue;

        t += tmp;
        for(int j = i; j <= rp; j++) c[j] = !c[j];
        rp = i - 1;
        tmp = 0;
    }

    if(t != 0){
        cout << "-1\n";
        return 0;
    }

    for(int i = 1; i <= 2 * n; i++){
        if(c[i] == 0) cout << "A";
        else cout << "B";
    }
    cout << "\n";

    return 0;
}

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