Submission #311811

#	Time	Username	Problem	Language	Result	Execution time	Memory
311811		hhh07	Sorting (IOI15_sorting)	C++14	100 / 100	465 ms	24312 KiB

sorting

#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include "sorting.h"

using namespace std;


int moze(int n, int s[], int m, int x[], int y[], int p[], int q[]){
    int pos[n], s_copy[n], s_copy2[n];
    
    for (int i = 0; i < n; i++)
        pos[s[i]] = i, s_copy[i] = s[i], s_copy2[i] = s[i];
    
    for (int i = 0; i < m; i++)
        swap(s[x[i]], s[y[i]]);
    
    int kraj_pos[n];
    for (int i = 0; i < n; i++)
        kraj_pos[s[i]] = i;
    
    int f[n], g[n];
    for (int i = 0; i < n; i++){
        f[i] = kraj_pos[s_copy[i]];
        g[kraj_pos[s_copy[i]]] = i;
    }
    
    int cnt = 0;
    for (int i = 0; i < m; i++){
        swap(f[x[i]], f[y[i]]);
        g[f[x[i]]] = x[i]; g[f[y[i]]] = y[i];
        
        swap(s_copy2[x[i]], s_copy2[y[i]]);
        pos[s_copy2[x[i]]] = x[i]; pos[s_copy2[y[i]]] = y[i];
        
        bool t = false;
        while(cnt < n){
            int idx = g[cnt];
            
            if (s_copy2[idx] != cnt){
                int a = idx, b = pos[cnt];
                swap(s_copy2[a], s_copy2[b]);
                p[i] = a; q[i] = b;
                pos[s_copy2[a]] = a; pos[s_copy2[b]] = b;
                t = true;
                break;
            }
            cnt++;
        }
        
        if (!t)
            p[i] = q[i] = 0;
        else
            cnt++;
    }
    for (int i = 0; i < n; i++)
        s[i] = s_copy[i];

    for (int i = 0; i < n; i++){
        if (s_copy2[i] != i)
            return false;
    }
    
    return true;
}

int findSwapPairs(int n, int s[], int m, int x[], int y[], int p[], int q[]) {
    int beg = 0, end = m;
    
    while(beg < end){
        int mid = (beg + end)/2;
        for (int i = 0; i < n; i++)
            p[i] = 0, q[i] = 0;
        if (moze(n, s, mid, x, y, p, q))
            end = mid;
        else
            beg = mid + 1;
    }
    
    if (moze(n, s, beg, x, y, p, q))
        return beg;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:83:1: warning: control reaches end of non-void function [-Wreturn-type]
   83 | }
      | ^

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