Submission #172169

#	Time	Username	Problem	Language	Result	Execution time	Memory
172169		emil_physmath	Nice sequence (IZhO18_sequence)	C++17	6 / 100	11 ms	9724 KiB

sequence

#include <algorithm>
#include <iostream>
#include <vector>
#include <set>
using namespace std;
typedef double ldouble;
typedef long long llong;
typedef unsigned int uint;
const int maxN = 100001;

vector<int> nei[400001];
int a[400001];
bool used[400001];

void DFS(int v, vector<int>& order)
{
    used[v] = true;
    for (int to: nei[v])
        if (!used[to])
            DFS(to, order);
    order.push_back(v);
}
bool Check(int n, int m, int len)
{
    if (len >= n)
    {
        llong sum = 0;
        for (int i = 1; i <= n; ++i)
            sum += a[i];
        if (sum >= 0) return false;
        for (int i = 2; i + n - 1 <= len; ++i)
        {
            sum -= a[i - 1];
            sum += a[i + n - 1];
            if (sum >= 0) return false;
        }
    }
    if (len >= m)
    {
        llong sum = 0;
        for (int i = 1; i <= m; ++i)
            sum += a[i];
        if (sum <= 0) return false;
        for (int i = 2; i + m - 1 <= len; ++i)
        {
            sum -= a[i - 1];
            sum += a[i + m - 1];
            if (sum <= 0) return false;
        }
    }
    return true;
}
int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    int t;
    cin >> t;
    while (t--)
    {
        int n, m;
        cin >> n >> m;
        int ans = max(n, m) - 1;
        vector<int> ansArr(max(n, m) - 1, n < m ? -1 : 1);
        int l = max(n, m)/* + 0.5 * min(n, m) - 1*/, r = 2 * max(n, m) - max(n, m) % min(n, m) - 1 - 1;
        r = min(r, n + m + max(n, m) % min(n, m) - 2);
        bool up = true;
        int prevLen = 0;
        while (l <= r)
        {
            int len = (l + r) / 2;
            for (int i = 0; i <= len; ++i)
            {
                used[i] = false;
                if (!up) vector<int>().swap(nei[i]);
            }
            for (int i = (up ? prevLen + 1 : 1); i <= len; ++i)
            {
                if (i - n >= 0)
                    nei[i].push_back(i - n);
                if (i - m >= 0)
                    nei[i - m].push_back(i);
            }
            vector<int> order;
            for (int i = 0; i <= len; ++i)
                if (!used[i])
                    DFS(i, order);
            reverse(order.begin(), order.end());
            vector<int> pref(len + 1);
            for (int i = 0; i < order.size(); ++i)
                pref[order[i]] = i;
            for (int i = 1; i < pref.size(); ++i)
                pref[i] -= pref[0];
            pref[0] = 0;
            for (int i = 1; i <= len; ++i)
                a[i] = pref[i] - pref[i - 1];
            if (Check(n, m, len))
            {
                ans = len;
                ansArr.resize(len);
                for (int i = 0; i < len; ++i)
                    ansArr[i] = a[i + 1];
                l = len + 1;
                up = true;
                prevLen = len;
            }
            else
            {
                r = len - 1;
                up = false;
            }
        }
        cout << ans << endl;
        for (int i = 0; i < ans; ++i)
            cout << ansArr[i] << ' ';
        cout << '\n';
    }
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:92:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int i = 0; i < order.size(); ++i)
                             ~~^~~~~~~~~~~~~~
sequence.cpp:94:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int i = 1; i < pref.size(); ++i)
                             ~~^~~~~~~~~~~~~

• Subtask 1: 6 / 6
• Subtask 2: 0 / 9
• Subtask 3: 0 / 14
• Subtask 4: 0 / 15
• Subtask 5: 0 / 14
• Subtask 6: 0 / 18
• Subtask 7: 0 / 24