Submission #252185

#	Time	Username	Problem	Language	Result	Execution time	Memory
252185		Hehehe	Sorting (IOI15_sorting)	C++14	20 / 100	1 ms	384 KiB

sorting

#include<bits/stdc++.h> //:3
using namespace std;
typedef long long ll;
#define all(a) (a).begin(), (a).end()
#define ff first
#define ss second
#define pb push_back
#define mp make_pair
#define rc(s) return cout<<s,0
#define pi pair <int, int>
#define sz(x) (int)((x).size())
#include "sorting.h"

const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};

const ll H = 2e3 + 11;

//ifstream in(".in");
//ofstream out(".out");

int pos[H];

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {

    int n = N, m = M, cur = 0;


    for(int i = 0; i < n; i++){
        pos[S[i]] = i;
        if(X[i] == 0 && Y[i] == 0)cur++;
    }

    vector<pi>ans;

    if(cur == n){//subtask 1, 2

        for(int i = 0; i < n; i++){
            if(S[i] == i)continue;
            ans.push_back({i, pos[i]});
            int x = i, y = S[i];
            swap(S[i], S[pos[i]]);
            pos[y] = pos[i];
            pos[x] = x;
        }

        int k = 0;
        for(auto it : ans){
            P[k] = it.ff;
            Q[k] = it.ss;
            k++;
        }

        return sz(ans);
    }else{//subtask 3

        swap(S[0], S[1]); //Ermek first move
        pos[S[0]] = 0;
        pos[S[1]] = 1;

        ans.push_back({pos[0], 1});
        int XX = pos[0], YY = 1;
        pos[S[1]] = pos[0];
        pos[0] = 0;

        swap(S[XX], S[YY]);
        swap(S[0], S[1]);
        //we put 0 on pos 1 then he swaps (0, 1) so we have the form 0, x, ..

        ans.push_back({pos[1], 1});
        int xx = pos[1], yy = 1;
        pos[S[0]] = pos[1];
        pos[1] = 1;

        swap(S[xx], S[yy]);
        swap(S[0], S[1]);
        //we put 1 on pos 1 then he swaps (0, 1) so we have the form 1, 0, ..

        S[0] = 1;
        S[1] = 0;

        for(int i = 2; i < n; i++){
            if(S[i] == i)continue;
            ans.push_back({i, pos[i]});
            int x = i, y = S[i];
            swap(S[i], S[pos[i]]);
            pos[y] = pos[i];
            pos[x] = x;

            //his move
            swap(S[0], S[1]);
        }

        if(S[0] != 0)ans.push_back({0, 1});

        int k = 0;
        for(auto it : ans){
            P[k] = it.ff;
            Q[k] = it.ss;
            k++;
        }

        return sz(ans);

    }
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:26:16: warning: unused variable 'm' [-Wunused-variable]
     int n = N, m = M, cur = 0;
                ^

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