제출 #986428

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
986428		borisAngelov	Bitaro's travel (JOI23_travel)	C++17	0 / 100	3097 ms	4184 KiB

travel

#include <bits/stdc++.h>

using namespace std;

const int maxn = 200005;

int n, q;

int a[maxn];

int toLeft[maxn];
int toRight[maxn];

int calcLeft(int pos)
{
    int l = 1;
    int r = pos - 1;

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

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

    if (l == pos)
    {
        return -1;
    }
    else
    {
        return l;
    }
}

int calcRight(int pos)
{
    int l = pos + 1;
    int r = n;

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

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

    if (r == pos)
    {
        return -1;
    }
    else
    {
        return r;
    }
}

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

    while (true)
    {
        if (toLeft[pos] != -1)
        {
            ans += a[pos] - a[toLeft[pos]];
            pos = toLeft[pos];
            minPos = min(minPos, pos);
        }
        else
        {
            ans += a[toRight[pos]] - a[pos];
            pos = toRight[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];
    }

    for (int i = 1; i <= n; ++i)
    {
        if (i == 1)
        {
            toLeft[i] = -1;
            toRight[i] = n;
        }
        else if (i == n)
        {
            toLeft[i] = 1;
            toRight[i] = -1;
        }
        else
        {
            toLeft[i] = calcLeft(i);
            toRight[i] = calcRight(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);
        long long ans = dist1 + simulate(where);

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

    return 0;
}

• Subtask 1: 0 / 5
• Subtask 2: 0 / 10
• Subtask 3: 0 / 30
• Subtask 4: 0 / 55