제출 #68071

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
68071		MKopchev	정렬하기 (IOI15_sorting)	C++14	100 / 100	247 ms	14184 KiB

sorting

#include<bits/stdc++.h>
#include "sorting.h"
using namespace std;
const int nmax=2e5+42;
int arr[nmax],where[nmax],inv[nmax];
bool been[nmax];
vector< pair<int,int> > change;
int findSwapPairs(int N,int S[],int M,int X[],int Y[],int P[],int Q[])
{
    memset(been,0,sizeof(been));
    change={};
    int ok=N,not_ok=-1;
    while(ok-not_ok>1)
    {
        int av=(ok+not_ok)/2;
        //test av
        for(int j=0;j<N;j++)
            arr[j]=S[j];

        for(int j=0;j<av;j++)
            swap(arr[X[j]],arr[Y[j]]);

        memset(been,0,sizeof(been));
        int now=0;
        for(int i=0;i<N;i++)
            if(been[i]==0)
            {
                int j=i,d=0;
                while(been[j]==0)
                {
                    been[j]=1;
                    d++;
                    j=arr[j];
                }
                now=now+d-1;
            }
        //cout<<av<<" -> "<<now<<endl;
        if(now<=av)ok=av;
        else not_ok=av;
    }
    for(int j=0;j<N;j++)
        arr[j]=S[j];
    for(int j=0;j<ok;j++)
        swap(arr[X[j]],arr[Y[j]]);

    memset(been,0,sizeof(been));
    for(int i=0;i<N;i++)
        if(been[i]==0)
        {
            int j=i,d=0;
            while(been[j]==0)
            {
                been[j]=1;
                d++;
                j=arr[j];
                if(i!=j)change.push_back({min(i,j),max(i,j)});
            }

        }
    while(change.size()<ok)
    {
        change.push_back({0,0});
    }
    for(auto k:change)
    {
    swap(arr[k.first],arr[k.second]);
    }

    for(int i=0;i<N;i++)
        if(arr[i]!=i)return -1;//???
    int SZ=change.size();
    //reverse(change.begin(),change.end());
    /*
    cout<<"change: "<<endl;
    for(auto k:change)cout<<k.first<<" "<<k.second<<endl;
    */
    /*
    for(int i=0;i<SZ;i++)
    {
        pair<int,int> now=change[i];
        for(int j=ok-1;j>i;j--)
        {
            if(X[j]==now.first&&Y[j]==now.second)continue;
            if(X[j]==now.second&&Y[j]==now.first)continue;
            int a=-1,b=-1,q=-1;
            if(X[j]==now.first)a=X[j],b=Y[j],q=now.second;
            else if(Y[j]==now.first)a=Y[j],b=X[j],q=now.second;
            else if(X[j]==now.second)a=X[j],b=Y[j],q=now.first;
            else if(Y[j]==now.second)a=Y[j],b=X[j],q=now.first;
            if(a!=-1)now={b,q};
            //cout<<"after "<<j<<" step, "<<now.first<<" "<<now.second<<endl;
        }
        P[i]=now.first;
        Q[i]=now.second;
        //cout<<i<<" -> "<<now.first<<" "<<now.second<<endl;
    }
    */
    for(int j=0;j<N;j++)
        where[j]=j,inv[j]=j;
    for(int i=ok-1;i>=0;i--)
    {
        P[i]=where[change[i].first];
        Q[i]=where[change[i].second];
        swap(where[inv[X[i]]],where[inv[Y[i]]]);
        swap(inv[X[i]],inv[Y[i]]);
    }
    //test
    for(int j=0;j<N;j++)
        arr[j]=S[j];
    for(int i=0;i<ok;i++)
    {
        swap(arr[X[i]],arr[Y[i]]);
        swap(arr[P[i]],arr[Q[i]]);
        //for(int j=0;j<N;j++)cout<<arr[j]<<" ";cout<<endl;
    }

    for(int i=0;i<N;i++)
        if(arr[i]!=i)
        {
            cout<<"---"<<endl;
            cout<<ok<<endl;
            for(int j=0;j<ok;j++)cout<<P[j]<<" "<<Q[j]<<endl;
            for(int j=0;j<N;j++)cout<<arr[j]<<" ";cout<<endl;
            system("pause");
        }

    return ok;
}
/*
int n=5;
int S[5]={4,3,2,1,0};
int m=6;
int X[6]={0,1,2,3,0,1};
int Y[6]={1,2,3,4,1,2};
int P[6];
int Q[6];
*/
/*
int n=3;
int S[3]={0,2,1};
int m=3;
int X[3]={0,1,2};
int Y[3]={1,2,0};
int P[3];
int Q[3];
*/
/*
const int n=5;
int S[n];
const int m=6;
int X[m]={1,4,2,1,0};
int Y[m]={1,0,3,4,4};
int P[m];
int Q[m];
int main()
{
    srand(time(0));
    while(1)
    {
        for(int j=0;j<n;j++)S[j]=j;
        random_shuffle(S,S+n);
        for(int j=0;j<m;j++)
        {
            X[j]=rand()%n;
            Y[j]=rand()%n;
        }
        cout<<n<<" : ";for(int j=0;j<n;j++)cout<<S[j]<<" ";cout<<endl;
        cout<<m<<endl;
        for(int j=0;j<m;j++)cout<<X[j]<<" "<<Y[j]<<endl;
        cout<<findSwapPairs(n,S,m,X,Y,P,Q)<<endl;
        cout<<endl;
    }
}
*/

컴파일 시 표준 에러 (stderr) 메시지

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:60:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(change.size()<ok)
           ~~~~~~~~~~~~~^~~
sorting.cpp:71:23: warning: conversion to 'int' from 'std::vector<std::pair<int, int> >::size_type {aka long unsigned int}' may alter its value [-Wconversion]
     int SZ=change.size();
            ~~~~~~~~~~~^~
sorting.cpp:123:13: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
             for(int j=0;j<N;j++)cout<<arr[j]<<" ";cout<<endl;
             ^~~
sorting.cpp:123:51: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
             for(int j=0;j<N;j++)cout<<arr[j]<<" ";cout<<endl;
                                                   ^~~~
sorting.cpp:71:9: warning: unused variable 'SZ' [-Wunused-variable]
     int SZ=change.size();
         ^~
sorting.cpp:8:37: warning: unused parameter 'M' [-Wunused-parameter]
 int findSwapPairs(int N,int S[],int M,int X[],int Y[],int P[],int Q[])
                                     ^
sorting.cpp:124:19: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
             system("pause");
             ~~~~~~^~~~~~~~~

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