Submission #568613

#	Time	Username	Problem	Language	Result	Execution time	Memory
568613		losmi247	Building 4 (JOI20_building4)	C++14	11 / 100	46 ms	78072 KiB

building4

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N = 2002;

int n,a[2*N],b[2*N];
int dp[2*N][2*N][2];

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cin >> n;
    for(int i = 1; i <= 2*n; i++){
        cin >> a[i];
    }
    for(int i = 1; i <= 2*n; i++){
        cin >> b[i];
    }

    dp[0][0][0] = dp[0][0][1] = 1;
    for(int i = 1; i <= 2*n; i++){
        for(int j = 0; j <= i; j++){
            if(j > 0 && a[i] >= a[i-1]) dp[i][j][0] |= dp[i-1][j-1][0];
            if(j > 0 && a[i] >= b[i-1]) dp[i][j][0] |= dp[i-1][j-1][1];

            if(b[i] >= a[i-1]) dp[i][j][1] |= dp[i-1][j][0];
            if(b[i] >= b[i-1]) dp[i][j][1] |= dp[i-1][j][1];
        }
    }

    int x = 2*n,y = n,z = 0;
    if(dp[x][y][z] == 0) z = 1;
    if(dp[x][y][z] == 0){
        cout << -1 << endl;
        return 0;
    }
    string s = "";
    while(x){
        if(z == 0){
            assert(y > 0);
            s += "A";
            if(a[x] >= a[x-1] && dp[x-1][y-1][0]){
                x--;
                y--;
                z = 0;
            }
            else{
                assert(a[x] >= b[x-1] && dp[x-1][y-1][1]);
                x--;
                y--;
                z = 1;
            }
        }
        else{
            s += "B";
            if(b[x] >= a[x-1] && dp[x-1][y][0]){
                x--;
                z = 0;
            }
            else{
                assert(b[x] >= b[x-1] && dp[x-1][y][1]);
                x--;
                z = 1;
            }
        }
    }

    reverse(s.begin(),s.end());
    cout << s << endl;
}

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