Submission #1072817

#	Time	Username	Problem	Language	Result	Execution time	Memory
1072817		jer033	Sprinklers (CEOI24_sprinklers)	C++17	3 / 100	58 ms	1624 KiB

Main

#include <bits/stdc++.h>
using namespace std;

vector<int> in_between;

bool possible(int K, vector<int> (&sprinks), vector<int> (&flowers))
{
    int N = sprinks.size();
    int M = flowers.size();
    int covered = -1;
    int towater = 0;
    int i = 0;
    while (i<N)
    {
        if (towater<M)
        {
            int loc = sprinks[i];
            if (flowers[towater]<loc)
            {
                if (flowers[towater] < (loc-K))
                    return 0;
                if (((i+1)<N) and (flowers[towater] >= (sprinks[i+1]-K)) and (in_between[i]>0))
                {
                    i++;
                    covered = loc+K;
                }
                else
                    covered = loc;
            }
            else
                covered = loc+K;

            while ((towater<M) and (flowers[towater]<=covered))
                towater++;
        }
        i++;
    }
    if (towater==M)
        return 1;
    return 0;
}

/*int seed=525697;

int rando(int a, int b)
{
    seed += a;
    seed = b*seed;
    seed = (seed*seed*seed + seed*seed*3 + 200*seed*seed*seed*b*seed + a*a*a);
    seed = abs(seed);
    int beed = seed%(b-a+1);
    return a + beed;
}

void check(int j)
{
    vector<int> spri;
    vector<int> flow;
    for (int i=0; i<10000; i++)
    {
        int k = rando(8, 170108);
        spri.push_back(k);
        if ((rando(1, 2)==1))
        {
            for (int j=0; j<rando(1, 8); j++)
                flow.push_back(rando(k-8, k));
        }
        else
        {
            for (int j=0; j<rando(1, 8); j++)
                flow.push_back(rando(k, k+8));
        } 
    }
    sort(spri.begin(), spri.end());
    sort(flow.begin(), flow.end());
    if (!possible(8, spri, flow))
        cout << "alert!!!" << j << '\n';
    else
        seed = 7812364+j*j*j*seed+seed*seed+5*seed+(seed%27263);
}*/

void report(int K, vector<int> (&sprinks), vector<int> (&flowers))
{
    cout << K << '\n';
    int N = sprinks.size();
    int M = flowers.size();
    int covered = -1;
    int towater = 0;
    int i = 0;
    while (i<N)
    {
        if (towater<M)
        {
            int loc = sprinks[i];
            if (flowers[towater]<loc)
            {
                if (((i+1)<N) and (flowers[towater] >= (sprinks[i+1]-K)) and (in_between[i]>0))
                {
                    i++;
                    covered = loc+K;
                    cout << "RL";
                }
                else
                {
                    covered = loc;
                    cout << 'L';
                }
            }
            else
            {
                covered = loc+K;
                cout << 'R';
            }

            while ((towater<M) and (flowers[towater]<=covered))
                towater++;
        }
        else
            cout << 'R';
        i++;
    }
    cout << '\n';
}

int main()
{
    int N, M;
    cin >> N >> M;
    vector<int> sprinks(N);
    vector<int> flowers(M);
    for (int i=0; i<N; i++)
        cin >> sprinks[i];
    for (int i=0; i<M; i++)
        cin >> flowers[i];
    if (N==1)
    {
        int left = flowers[0]-sprinks[0];
        int righ = flowers[M-1]-sprinks[0];
        if ((left<0) and (righ>0))
            cout << "-1\n";
        else
        {
            cout << max(abs(left), abs(righ)) << '\n';
            if (left<0)
                cout << "L\n";
            else
                cout << "R\n";
        }
    }
    else
    {
        in_between = vector<int> (N-1, 0);
        int curr = 0;
        for (int i=0; i<M; i++)
        {
            while (((curr+1)<N) and (flowers[i]>=sprinks[curr+1]))
                curr++;
            if (((curr+1)<N) and (flowers[i]>sprinks[curr]) and (flowers[i]<sprinks[curr+1]))
                in_between[curr]++;
        }

        bool tapos = 0;
        for (int guess = 0; guess<=20; guess++)
        {
            if ((!tapos) and possible(guess, sprinks, flowers))
            {
                report(guess, sprinks, flowers);
                tapos = 1;
            }
        }
        //for (int i=0; i<(N-1); i++)
            //cout << in_between[i] << '\n';

        /*int lo = 0;
        int hi = 1'000'000'005;
        while (lo!=hi)
        {
            int mid = (lo+hi)/2;
            if (possible(mid, sprinks, flowers))
                hi = mid;
            else
                lo = mid+1;
        }
        report(lo, sprinks, flowers);*/
    }
}

• Subtask 0: 0 / 0
• Subtask 1: 3 / 3
• Subtask 2: 0 / 6
• Subtask 3: 0 / 17
• Subtask 4: 0 / 27
• Subtask 5: 0 / 47