Submission #986436

#	Time	Username	Problem	Language	Result	Execution time	Memory
986436		borisAngelov	Bitaro's travel (JOI23_travel)	C++17	100 / 100	354 ms	7292 KiB

travel

#include <bits/stdc++.h>

using namespace std;

const int maxn = 200005;

int n, q;

int a[maxn];

long long simulate(int pos)
{
    long long ans = 0;

    int minPos = pos;
    int maxPos = pos;

    while (true)
    {
        //cout << "now " << pos << endl;
        //for (int i = 0; i < 1e9; ++i);
        if (pos == 1)
        {
            ans += (a[n] - a[1]);
            maxPos = n;
        }
        else if (pos == n)
        {
            ans += (a[n] - a[1]);
            minPos = 1;
        }
        else
        {
            //cout << "decide " << pos << " " << minPos << " " << maxPos << endl;
            if (a[pos] - a[minPos - 1] <= a[maxPos + 1] - a[pos]) // go left
            {
                //cout << "LEFT" << endl;
                int l = 1;
                int r = pos - 1;

                while (l <= r)
                {
                    int mid = (l + r) / 2;

                    if (a[pos] - a[mid] <= a[maxPos + 1] - a[pos])
                    {
                        r = mid - 1;
                    }
                    else
                    {
                        l = mid + 1;
                    }
                }

                ans += (a[pos] - a[l]);
                pos = l;
            }
            else // go right
            {
                //cout << "RIGHT" << endl;
                int l = pos + 1;
                int r = n;

                while (l <= r)
                {
                    int mid = (l + r) / 2;

                    if (a[mid] - a[pos] < a[pos] - a[minPos - 1])
                    {
                        l = mid + 1;
                    }
                    else
                    {
                        r = mid - 1;
                    }
                }

                ans += (a[r] - a[pos]);
                pos = r;
            }

            minPos = min(minPos, pos);
            maxPos = max(maxPos, pos);
        }

        if (minPos == 1 && maxPos == n)
        {
            break;
        }
    }

    return ans;
}

void fastIO()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
}

int main()
{
    fastIO();

    cin >> n;

    for (int i = 1; i <= n; ++i)
    {
        cin >> a[i];
    }

    cin >> q;

    for (int i = 1; i <= q; ++i)
    {
        int x;
        cin >> x;

        int nxt = lower_bound(a + 1, a + n + 1, x) - a;
        int prv = nxt - 1;
        int where = -1;

        if (prv <= 0)
        {
            where = nxt;
        }
        else if (nxt > n)
        {
            where = prv;
        }
        else
        {
            if (x - a[prv] <= a[nxt] - x)
            {
                where = prv;
            }
            else
            {
                where = nxt;
            }
        }

        int dist1 = abs(a[where] - x);

        if (n == 1)
        {
            cout << dist1 << "\n";
            continue;
        }

        long long ans = dist1 + simulate(where);

        cout << ans << "\n";
    }

    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 30 / 30
• Subtask 4: 55 / 55