Submission #306839

#	Time	Username	Problem	Language	Result	Execution time	Memory
306839		MrDomino	Monochrome Points (JOI20_monochrome)	C++14	25 / 100	2072 ms	404 KiB

monochrome

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;
typedef long double ld;

const int N = (int) 2e5 + 7;
int n;
string s;
vector<int> a;
vector<int> b;

int f(int l, int r, int x)
{
    return (l <= x && x <= r);
}

ll get(int k)
{
    vector<pair<int, int>> p;
    for (int i = 0; i < n; i++)
    {
        p.push_back({a[i], b[(i + k) % n]});
    }
    for (auto &it : p)
    {
        if (it.second < it.first)
        {
            swap(it.first, it.second);
        }
    }
    sort(p.begin(), p.end());
    ll sol = 0;
    for (int i = 0; i < (int) p.size(); i++)
    {
        for (int j = 0; j < i; j++)
        {
            sol += (p[i].first <= p[j].second && p[j].second <= p[i].second);
        }
    }
    return sol;
}

int main()
{
    ios::sync_with_stdio(0);
    cin.tie(0);

    cin >> n >> s;
    for (int i = 0; i < 2 * n; i++)
    {
        if (s[i] == 'W')
        {
            a.push_back(i);
        }
        else
        {
            b.push_back(i);
        }
    }
    ll sol = 0;
    for (int k = 0; k < n; k++)
    {
        sol = max(sol, get(k));
    }
    cout << sol << "\n";
}

• Subtask 1: 4 / 4
• Subtask 2: 21 / 21
• Subtask 3: 0 / 10
• Subtask 4: 0 / 65