Submission #592352

#	Time	Username	Problem	Language	Result	Execution time	Memory
592352		Hanksburger	Building 4 (JOI20_building4)	C++17	100 / 100	261 ms	28652 KiB

building4

#include <bits/stdc++.h>
using namespace std;
int a[1000005], b[1000005];
int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    int n, l=0, r=0, k=0, cnt=0;
    cin >> n;
    for (int i=1; i<=n*2; i++)
        cin >> a[i];
    for (int i=1; i<=n*2; i++)
        cin >> b[i];
    for (int i=2; i<=n*2; i++)
    {
        int mn=min(a[i-1]==-1?2e9:a[i-1], b[i-1]==-1?2e9:b[i-1]);
        if (a[i]<mn)
            a[i]=-1;
        if (b[i]<mn)
            b[i]=-1;
    }
    for (int i=n*2-1; i>=1; i--)
    {
        int mx=max(a[i+1], b[i+1]);
        if (a[i]>mx)
            a[i]=-1;
        if (b[i]>mx)
            b[i]=-1;
    }
    for (int i=1; i<=n*2; i++)
    {
        if (a[i]==-1 && b[i]==-1)
        {
            cout << -1;
            return 0;
        }
        else if (b[i]==-1)
        {
            l++;
            r++;
            k++;
        }
        else if (a[i]!=-1)
        {
            int x=0, y=0, mn=0, mx=0;
            while (i<n*2 && a[i+1]!=-1 && b[i+1]!=-1 && max(a[i], b[i])>min(a[i+1], b[i+1]))
            {
                if (a[i]>b[i])
                {
                    x++;
                    y--;
                }
                else
                    y++;
                mn=min(mn, y);
                mx=max(mx, y);
                i++;
            }
            if (a[i]>b[i])
            {
                x++;
                y--;
            }
            else
                y++;
            l+=x+min(mn, y);
            r+=x+max(mx, y);
            k+=x;
        }
    }
    if (n<l || r<n)
    {
        cout << -1;
        return 0;
    } /*
    for (int i=1; i<=n*2; i++)
        cout << a[i] << ' ';
    cout << '\n';
    for (int i=1; i<=n*2; i++)
        cout << b[i] << ' ';
    cout << '\n';
    cout << "l r " << l << ' ' << r << '\n'; */
    for (int i=1; i<=n*2; i++)
    {
        if (a[i]==-1)
            cout << 'B';
        else if (b[i]==-1)
            cout << 'A';
        else
        {
            int ind=i, y=0, mn=0, mx=0, tar;
            while (ind<n*2 && a[ind+1]!=-1 && b[ind+1]!=-1 && max(a[ind], b[ind])>min(a[ind+1], b[ind+1]))
            {
                if (a[ind]>b[ind])
                    y--;
                else
                    y++;
                mn=min(mn, y);
                mx=max(mx, y);
                ind++;
            }
            if (a[ind]>b[ind])
                y--;
            else
                y++;
            mn=min(mn, y);
            mx=max(mx, y);
            if (k+cnt<=n)
                tar=min(n-k-cnt, mx);
            else
                tar=max(n-k-cnt, mn);
            cnt+=tar;
            y=0;
            while (i<n*2 && a[i+1]!=-1 && b[i+1]!=-1 && max(a[i], b[i])>min(a[i+1], b[i+1]))
            {
                if (y==tar)
                {
                    if (a[i]>b[i])
                        cout << 'A';
                    else
                        cout << 'B';
                }
                else
                {
                    if (a[i]>b[i])
                    {
                        cout << 'B';
                        y--;
                    }
                    else
                    {
                        cout << 'A';
                        y++;
                    }
                }
                i++;
            }
            if (y==tar)
            {
                if (a[i]>b[i])
                    cout << 'A';
                else
                    cout << 'B';
            }
            else
            {
                if (a[i]>b[i])
                    cout << 'B';
                else
                    cout << 'A';
            }
        }
    }
    return 0;
}

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