Submission #1147137

#	Time	Username	Problem	Language	Result	Execution time	Memory
1147137		alexdd	Sorting (IOI15_sorting)	C++20	100 / 100	218 ms	21100 KiB

sorting

#include "sorting.h"
#include<bits/stdc++.h>
using namespace std;
int n,m;
pair<int,int> his[600005],sol[600005];
int init[200005],ord[200005],unde[200005],final[200005],ufin[200005];
bool is_sorted()
{
    for(int i=1;i<n;i++)
        if(ord[i]<ord[i-1])
            return 0;
    return 1;
}
bool verif(int ult)
{
    for(int i=0;i<n;i++)
        ord[i] = final[i] = init[i];
    for(int i=0;i<=ult;i++)
        swap(final[his[i].first], final[his[i].second]);

    for(int i=0;i<n;i++)
        unde[ord[i]] = i;
    for(int i=0;i<n;i++)
        ufin[final[i]] = i;

    vector<int> gresite;
    for(int i=0;i<n;i++)
        if(final[i]!=i)
            gresite.push_back(i);
    int poz=0;

    for(int pas=0;pas<=ult;pas++)
    {
        swap(unde[ord[his[pas].first]], unde[ord[his[pas].second]]);
        swap(ord[his[pas].first],ord[his[pas].second]);

        pair<int,int> aux = {-1,-1};
        while(poz<gresite.size() && final[gresite[poz]]==gresite[poz])
            poz++;
        if(poz < gresite.size())
            aux = {final[gresite[poz]], gresite[poz]};

        if(aux.first!=-1)
        {
            sol[pas].first = unde[aux.first];
            sol[pas].second = unde[aux.second];

            swap(ufin[aux.first], ufin[aux.second]);
            swap(final[ufin[aux.first]], final[ufin[aux.second]]);



            swap(unde[ord[sol[pas].first]], unde[ord[sol[pas].second]]);
            swap(ord[sol[pas].first], ord[sol[pas].second]);
        }
        else
            sol[pas] = {0,0};
    }
    for(int i=0;i<n;i++)
        ord[i] = init[i];
    for(int pas=0;pas<=ult;pas++)
    {
        swap(ord[his[pas].first], ord[his[pas].second]);
        swap(ord[sol[pas].first], ord[sol[pas].second]);
    }

    return is_sorted();
}
int findSwapPairs(int N, int copS[], int M, int X[], int Y[], int P[], int Q[])
{
    n = N;
    m = M;
    for(int i=0;i<N;i++)
    {
        init[i] = copS[i];
        ord[i] = init[i];
    }
    for(int i=0;i<M;i++)
    {
        his[i] = {X[i], Y[i]};
    }

    if(is_sorted())
        return 0;
    int st=0,dr=m-2,ans=m-1;
    while(st<=dr)
    {
        int mij=(st+dr)/2;
        if(verif(mij))
        {
            ans = mij;
            dr = mij-1;
        }
        else
            st = mij+1;
    }
    assert(verif(ans));
    for(int i=0;i<=ans;i++)
    {
        P[i] = sol[i].first;
        Q[i] = sol[i].second;
    }
    return ans+1;
}

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 16 / 16
• Subtask 4: 18 / 18
• Subtask 5: 20 / 20
• Subtask 6: 26 / 26