Submission #1057284

#	Time	Username	Problem	Language	Result	Execution time	Memory
1057284		Ghulam_Junaid	Sorting (IOI15_sorting)	C++17	20 / 100	1 ms	2652 KiB

sorting

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

const int MXN = 2e5 + 100;
int n, m, a[MXN], p[MXN], pos[MXN], tmp[MXN], pos_box[MXN];

bool is_sorted(){
    bool good = 1;
    for (int i = 1; i < n; i ++)
        good &= (a[i] >= a[i - 1]);
    return good;
}

int findSwapPairs(int N, int s[], int M, int x[], int y[], int rx[], int ry[]){
    n = N, m = M;
    for (int i = 0; i < n; i ++)
        a[i] = s[i];

    if (is_sorted())
        return 0;

    int l = 0;
    int r = n;

    while (r - l > 1){
        int mid = (l + r) / 2;
        
        for (int i = 0; i < n; i ++)
            p[i] = tmp[i] = i, a[i] = s[i], pos[a[i]] = i, pos_box[i] = i;
        for (int i = 0; i < mid; i ++)
            swap(p[x[i]], p[y[i]]);
      
        int steps = 0;
        
        bool move = 0;
        for (int i = 0, j = 0; i < n and j < mid;){
            if (!move){
                swap(pos_box[tmp[x[j]]], pos_box[tmp[y[j]]]);
                swap(tmp[x[j]], tmp[y[j]]);
                swap(pos[a[x[j]]], pos[a[y[j]]]);
                swap(a[x[j]], a[y[j]]);

                move = 1;
                continue;
            }
          
            if (pos[i] == pos_box[p[i]]){
                i++;
                continue;
            }

            move = 0;

            rx[j] = pos[i], ry[j] = pos_box[p[i]];
            swap(pos[i], pos[a[ry[j]]]);
            swap(a[rx[j]], a[ry[j]]);

            i++;
            j++;
        }

        if (is_sorted())
            r = mid;
        else
            l = mid;
    }
    return r;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:34:13: warning: unused variable 'steps' [-Wunused-variable]
   34 |         int steps = 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