Submission #314601

#	Time	Username	Problem	Language	Result	Execution time	Memory
314601		amunduzbaev	Sorting (IOI15_sorting)	C++14	20 / 100	2 ms	544 KiB

sorting

//#include "grader.cpp"
#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
const int N=2*1e5+5;
int n, s[N], x[N], y[N];

vector<pair<int,int>>ans;
bool check(int m){
    int a[N], pos[N];
    for(int i=0;i<n;i++) a[i]=s[i];
    for(int i=0;i<m;i++) swap(a[x[i]], a[y[i]]);
    for(int i=0;i<n;i++) pos[a[i]]=i;

    vector<pair<int,int > > swaps;
    for(int i=0;i<n;i++){
        if(pos[i]!=i){
            int j=pos[i];
            swaps.push_back({a[i],a[j]});
            pos[a[i]]=j;
            swap(a[i],a[j]);
        }
    }

    if(swaps.size()>m) return false;
    ans.clear();
    /*
    cout<<m<<"\n";
    for(int i=0;i<swaps.size();i++){
        cout<<swaps[i].first<<" "<<swaps[i].second<<"\n";
    }
    */
    ans.assign(m, {0,0});
    for(int i=0;i<n;i++) a[i]=s[i], pos[a[i]]=i;
    for(int i=0;i<swaps.size();i++){
        int x1=x[i], y1=y[i], i1=swaps[i].first, j1=swaps[i].second;
        ans[i] = {pos[i1],pos[j1]};
        i1=pos[i1],j1=pos[j1];
        swap ( a[x1] ,a[y1] );
        swap ( a[i1], a[j1] );
        swap ( pos[a[x1]], pos[a[y1]] );
        swap ( pos[a[i1]], pos[a[j1]] );
    }
    return true;
}

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    n=N;
    for(int i=0;i<n;i++) s[i]=S[i];
    for(int i=0;i<M;i++) x[i]=X[i], y[i]=Y[i];
    int l=0,r=M;
    while(l<r){
        int md=l+((r-l)/2);
        if(check(md)) r=md;
        else l=md+1;
    }
    for(int i=0;i<ans.size();i++){
        P[i]=ans[i].first;
        Q[i]=ans[i].second;
    }
	return l;

}

Compilation message (stderr)

sorting.cpp: In function 'bool check(int)':
sorting.cpp:25:20: warning: comparison of integer expressions of different signedness: 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   25 |     if(swaps.size()>m) return false;
      |        ~~~~~~~~~~~~^~
sorting.cpp:35:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   35 |     for(int i=0;i<swaps.size();i++){
      |                 ~^~~~~~~~~~~~~
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:47:76: warning: declaration of 'N' shadows a global declaration [-Wshadow]
   47 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
      |                                                                            ^
sorting.cpp:5:11: note: shadowed declaration is here
    5 | const int N=2*1e5+5;
      |           ^
sorting.cpp:57:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   57 |     for(int i=0;i<ans.size();i++){
      |                 ~^~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 12 / 12
• Subtask 3: 0 / 16
• Subtask 4: 0 / 18
• Subtask 5: 0 / 20
• Subtask 6: 0 / 26