Submission #970803

#	Time	Username	Problem	Language	Result	Execution time	Memory
970803		Aiperiii	Building 4 (JOI20_building4)	C++14	0 / 100	288 ms	524288 KiB

building4

#include <bits/stdc++.h>
#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
const int N=2e3+5;
int a[N*2],b[N*2],dp[N*2][N][2];
vector <int> pr[N*2][N][2];
signed main(){
    ios_base::sync_with_stdio();
    cin.tie(0);cout.tie(0);
    int n;
    cin>>n;
    for(int i=1;i<=n*2;i++)cin>>a[i];
    for(int i=1;i<=n*2;i++)cin>>b[i];
    dp[0][0][0]=1;
    for(int i=1;i<=n*2;i++){
        for(int j=0;j<=min(i,n);j++){
            if(a[i]>=a[i-1]){
                dp[i][j][0]=dp[i-1][j][0];
                pr[i][j][0]={i-1,j,0};
            }
            if(a[i]>=b[i-1] && !dp[i][j][0]){
                dp[i][j][0]=dp[i-1][j][1];
                pr[i][j][0]={i-1,j,1};
            }
            if(j-1>=0){
                if(b[i]>=a[i-1]){
                    dp[i][j][1]=dp[i-1][j-1][0];
                    pr[i][j][1]={i-1,j-1,0};
                }
                if(b[i]>=b[i-1] && !dp[i][j][1]){
                    dp[i][j][1]=dp[i-1][j-1][1];
                    pr[i][j][1]={i-1,j-1,1};
                }
            }
        }
    }
    int x=n*2,y=n,z=-1;
    string res="";
    if(dp[n*2][n][1]==1)z=1;
    if(dp[n*2][n][0]==1)z=0;
    if(z==-1){
        cout<<-1<<"\n";
        return 0;
    }
    while(x>=1){
        if(z==1)res+='B';
        else res+='A';
        vector <int> v=pr[x][y][z];
        x=v[0];
        y=v[1];
        z=v[2];
    }
    reverse(all(res));
    cout<<res<<"\n";
}
/*
 
3
0 9
8 1
13 7
 
*/

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