제출 #1045719

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
1045719		SamAnd	Sprinklers (CEOI24_sprinklers)	C++17	9 / 100	46 ms	12884 KiB

Main

#include <bits/stdc++.h>
using namespace std;
#define m_p make_pair
#define all(x) (x).begin(),(x).end()
#define sz(x) ((int)(x).size())
#define fi first
#define se second
typedef long long ll;
mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());
mt19937 rnf(2106);
const int N = 100005;

int n, m;
int s[N], f[N];

vector<pair<int, pair<int, int> > > v[N];
vector<int> vv[N];

int dp[N];
pair<pair<int, int>, pair<int, int> > p[N];
bool stg(int k)
{
    for (int i = 0; i <= n + 1; ++i)
    {
        dp[i] = 0;
        v[i].clear();
        vv[i].clear();
    }
    for (int i = 1; i < n; ++i)
    {
        if (s[i] + k <= s[i + 1] - k)
        {
            int l = s[i + 1] - k;
            int r = s[i] + k;

            int ri = i + 1;
            while (ri + 1 <= n && s[ri + 1] <= r)
            {
                ++ri;
                r = s[ri] + k;
            }

            int li = i;
            while (li - 1 >= 1 && s[li - 1] >= l)
            {
                --li;
                l = s[li] - k;
            }

            v[li].push_back(m_p(ri, m_p(l, r)));
            vv[li].push_back(i);
        }
    }

    for (int i = 0; i < n; ++i)
    {
        for (int j = 0; j < sz(v[i + 1]); ++j)
        {
            int l = v[i + 1][j].se.fi;
            int r = v[i + 1][j].se.se;
            int x = dp[i] + 1;
            while (x <= m && l <= f[x] && f[x] <= r)
                ++x;
            if (x - 1 > dp[v[i + 1][j].fi])
            {
                dp[v[i + 1][j].fi] = x - 1;
                p[v[i + 1][j].fi] = m_p(m_p(i, vv[i + 1][j]), m_p(i + 1, v[i + 1][j].fi));
            }
        }
        {
            int l = s[i + 1];
            int r = s[i + 1] + k;
            int x = dp[i] + 1;
            while (x <= m && l <= f[x] && f[x] <= r)
                ++x;
            if (x - 1 > dp[i + 1])
            {
                dp[i + 1] = x - 1;
                p[i + 1] = m_p(m_p(i, i), m_p((i + 1), -(i + 1)));
            }
        }
        {
            int l = s[i + 1] - k;
            int r = s[i + 1];
            int x = dp[i] + 1;
            while (x <= m && l <= f[x] && f[x] <= r)
                ++x;
            if (x - 1 > dp[i + 1])
            {
                dp[i + 1] = x - 1;
                p[i + 1] = m_p(m_p(i, i), m_p(-(i + 1), (i + 1)));
            }
        }
    }

    return (dp[n] == m);
}

void solv()
{
    cin >> n >> m;
    for (int i = 1; i <= n; ++i)
        cin >> s[i];
    for (int i = 1; i <= m; ++i)
        cin >> f[i];

    int l = 0, r = 1000000009;
    int ans = -1;
    while (l <= r)
    {
        int m = (l + r) / 2;
        if (stg(m))
        {
            ans = m;
            r = m - 1;
        }
        else
            l = m + 1;
    }

    cout << ans << "\n";
    if (ans != -1)
    {
        stg(ans);
        string s;
        s.assign(n + 1, '?');
        int i = n;
        while (i >= 1)
        {
            auto t = p[i];
            if (t.se.fi > 0 && t.se.se > 0)
            {
                int j = t.fi.se;
                s[j] = 'R';
                s[j + 1] = 'L';
                for (int k = j + 2; k <= t.se.se; ++k)
                    s[k] = 'R';
                for (int k = j - 1; k >= t.se.fi; --k)
                    s[k] = 'L';
            }
            else
            {
                if (t.se.fi < 0)
                {
                    s[t.se.se] = 'L';
                }
                else
                {
                    s[t.se.fi] = 'R';
                }
            }
            i = t.fi.fi;
        }
        reverse(all(s));
        s.pop_back();
        reverse(all(s));
        cout << s << "\n";
    }
}

int main()
{
    #ifdef SOMETHING
    freopen("input.txt", "r", stdin);
    //freopen("output.txt", "w", stdout);
    #endif // SOMETHING
    ios_base::sync_with_stdio(false), cin.tie(0);

    int tt = 1;
    //cin >> tt;
    while (tt--)
    {
        solv();
    }
    return 0;
}

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