Submission #292237

#	Time	Username	Problem	Language	Result	Execution time	Memory
292237		stoyan_malinin	Gondola (IOI14_gondola)	C++14	25 / 100	18 ms	1024 KiB

gondola

#include "gondola.h"
//#include "grader.cpp"

#include <set>
#include <vector>
#include <cstring>
#include <assert.h>
#include <iostream>
#include <algorithm>

using namespace std;

const int MAXN = 3e5 + 5;

namespace Valid
{
    bool seen[MAXN];
    bool sortedL[MAXN], sortedR[MAXN];

    void fillSeen(int n, int a[], int maxVal)
    {
        for(int i = 0;i<=maxVal;i++)
        {
            seen[i] = false;
        }
        for(int i = 0;i<n;i++)
        {
            seen[ a[i] ] = true;
        }
    }

    bool check(int n, int a[], int relevant)
    {
        int maxVal = 0;
        for(int i = 0;i<n;i++)
        {
            maxVal = max(maxVal, a[i]);
            sortedL[i] = sortedR[i] = false;
        }

        for(int i = 0;i<=maxVal;i++)
        {
            seen[i] = false;
        }

        for(int i = 0;i<n;i++)
        {
            if(seen[ a[i] ]==true) return false;
            seen[ a[i] ] = true;
        }

        sortedL[0] = true;
        for(int i = 1;i<n;i++)
        {
            if(a[i]>relevant) sortedL[i] = sortedL[i-1];
            else sortedL[i] = (sortedL[i-1]&(a[i-1]<a[i]));
        }

        sortedR[n-1] = true;
        for(int i = n-2;i>=0;i--)
        {
            if(a[i]>relevant) sortedR[i] = sortedR[i+1];
            else sortedR[i] = (sortedR[i+1]&(a[i]<a[i+1]));
        }

        if(sortedL[n-1]==true && (a[n-1]==n || (a[n-1]>relevant && seen[n]==false))) return true;
        for(int i = 0;i<n-1;i++)
        {
            if(sortedL[i]==true && sortedR[i+1]==true)
            {
                if(a[i]>relevant || a[i+1]>relevant)
                {
                    if((a[i]>relevant && seen[n]==false) && (a[i+1]>relevant && seen[1]==false))
                    {
                        return true;
                    }
                }
                else
                {
                    if(a[i]==n && a[i+1]==1)
                    {
                        return true;
                    }
                }
            }
        }

        return false;
    }
};

namespace Replacement
{
    vector <int> constructSlow(int n, int a[])
    {
        int maxVal = 0;
        for(int i = 0;i<n;i++) maxVal = max(maxVal, a[i]);

        vector <int> answer;
        for(int num = maxVal;num>=n+1;num--)
        {
            int ind = -1;
            for(int i = 0;i<n;i++)
            {
                if(a[i]==num)
                {
                    ind = i;
                    break;
                }
            }

            bool found = false;

            Valid::fillSeen(n, a, num);
            assert(Valid::seen[num]==true);

            for(int x = num-1;x>=1;x--)
            {
                if(Valid::seen[x]==false)
                {
                    a[ind] = x;
                    if(Valid::check(n, a, num-1)==true)
                    {
                        found = true;

                        answer.push_back(x);
                        break;
                    }

                    a[ind] = num;
                }
            }

            //assert(found==true);
        }

        reverse(answer.begin(), answer.end());
        return answer;
    }
};

int valid(int n, int inputSeq[])
{
  return Valid::check(n, inputSeq, n);
}

//----------------------

int replacement(int n, int gondolaSeq[], int replacementSeq[])
{
    vector <int> answer = Replacement::constructSlow(n, gondolaSeq);

    for(int i = 0;i<answer.size();i++)
    {
        replacementSeq[i] = answer[i];
        //assert(answer[i]<=n+i);
    }
    return answer.size();
}

//----------------------

int countReplacement(int n, int inputSeq[])
{
  return -3;
}

Compilation message (stderr)

gondola.cpp: In function 'std::vector<int> Replacement::constructSlow(int, int*)':
gondola.cpp:112:18: warning: variable 'found' set but not used [-Wunused-but-set-variable]
  112 |             bool found = false;
      |                  ^~~~~
gondola.cpp: In function 'int replacement(int, int*, int*)':
gondola.cpp:153:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  153 |     for(int i = 0;i<answer.size();i++)
      |                   ~^~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 10 / 10
• Subtask 4: 5 / 5
• Subtask 5: 0 / 10
• Subtask 6: 0 / 20
• Subtask 7: 0 / 5
• Subtask 8: 0 / 15
• Subtask 9: 0 / 15
• Subtask 10: 0 / 10