oj.uz

Submission #906109

# Submission time Handle Problem Language Result Execution time Memory
906109 2024-01-13T14:05:05 Z alexdd Building 4 (JOI20_building4) C++17
0 / 100
 3 ms 4700 KB 
#include<bits/stdc++.h>
using namespace std;
const int INF = 2e9;
int n;
int a[1000005];
int b[1000005];
pair<int,int> dp[1000005][2];
pair<int,int> emp = {-1,-1};
pair<int,int> combine(pair<int,int> x, pair<int,int> y)
{
    if(x==emp)
        return y;
    if(y==emp)
        return x;
    return {min(x.first,y.first), max(x.second,y.second)};
}
signed main()
{
    ios_base::sync_with_stdio(0);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[1][0] = {1,1};
    dp[1][1] = {0,0};
    for(int i=2;i<=2*n;i++)
    {
        dp[i][0] = emp;
        dp[i][1] = emp;
        if(a[i]>=a[i-1])
        {
            dp[i][0] = combine(dp[i][0], {dp[i-1][0].first+1, dp[i-1][0].second+1});
        }
        if(a[i]>=b[i-1])
        {
            dp[i][0] = combine(dp[i][0], {dp[i-1][1].first+1, dp[i-1][1].second+1});
        }
        if(b[i]>=a[i-1])
        {
            dp[i][1] = combine(dp[i][1], dp[i-1][0]);
        }
        if(b[i]>=b[i-1])
        {
            dp[i][1] = combine(dp[i][1], dp[i-1][1]);
        }
    }
    if((dp[2*n][0].first<=n && dp[2*n][0].second>=n) || (dp[2*n][1].first<=n && dp[2*n][1].second>=n))
    {
        int cur = n, ult = INF;
        string s = "";
        for(int i=2*n;i>0;i--)
        {
            if(dp[i][0].first<=cur && dp[i][0].second>=cur && a[i] <= ult)
            {
                ult = a[i];
                s.push_back('A');
                cur--;
            }
            else
            {
                ult = b[i];
                s.push_back('B');
            }
        }
        reverse(s.begin(),s.end());
        cout<<s;
    }
    else
        cout<<-1;
    return 0;
}

Subtask #1
0 / 11.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4440 KB Output is correct
2 Correct 2 ms 4444 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4440 KB Output is correct
5 Correct 3 ms 4700 KB Output is correct
6 Incorrect 2 ms 4700 KB Output isn't correct
7 Halted 0 ms 0 KB -

Subtask #2
0 / 89.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 4440 KB Output is correct
2 Correct 2 ms 4444 KB Output is correct
3 Correct 1 ms 4444 KB Output is correct
4 Correct 1 ms 4440 KB Output is correct
5 Correct 3 ms 4700 KB Output is correct
6 Incorrect 2 ms 4700 KB Output isn't correct
7 Halted 0 ms 0 KB -