Submission #600168

#	Time	Username	Problem	Language	Result	Execution time	Memory
600168		PiejanVDC	Sorting (IOI15_sorting)	C++17	20 / 100	2 ms	596 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;

int findSwapPairs(int n, int s[], int m, int X[], int Y[], int P[], int Q[]) {
    auto sorted = [&] (vector<int>&v) -> bool {
        for(int i = 0 ; i < n ; i++)
            if(v[i] != i)
                return 0;
        return 1;
    };
    for(int T = 1 ; T <= m ; T++) {
        //cout << "T : " << T << '\n';
        vector<int>c(n);
        for(int i = 0 ; i < n ; i++) c[i]= i;
        for(int i = 0 ; i < T ; i++)
            swap(c[X[i]], c[Y[i]]);
        vector<int>go(n, -1);
        for(int i = 0 ; i < n ; i++) {
            //assert(go[c[i]] == -1);
            go[c[i]] = i;
            assert(c[i] == i);
        }
        vector<int>v(n);
        auto S = [&] (int W) {
            for(int i = 0 ; i < n ; i++)
                if(v[i] == W)
                    return i;
            //assert(0);
        };
        for(int i = 0 ; i < n ; i++) v[i] = s[i];
        int cnt = 0;
        for(int i = 0 ; i < T ; i++) {
            if(sorted(v))
                return cnt;
            cnt++;
            swap(v[X[i]], v[Y[i]]);
            swap(go[X[i]], go[Y[i]]);
            int j;
            for(j = 0 ; j < n ; j++) {
                if(go[j] != v[j]) {
                    int p = S(go[j]);
                    P[cnt-1] = p;
                    Q[cnt-1] = j;
                    swap(v[p], v[j]);
                    break;
                }
            }
            /*cout << "    " << i << '\n';
            cout << "    ";
            for(auto z : v)
                cout << z << ' ';
            cout << '\n';*/
            if(j == n)
                P[cnt-1] = 0, Q[cnt-1] = 0;
            // do the swappings
            // look for first element not correct in go
        }
        if(sorted(v))
            return cnt;
    }
   assert(0);
   return 0;
}

Compilation message (stderr)

sorting.cpp: In lambda function:
sorting.cpp:30:9: warning: control reaches end of non-void function [-Wreturn-type]
   30 |         };
      |         ^

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