Submission #438874

#	Time	Username	Problem	Language	Result	Execution time	Memory
438874		NintsiChkhaidze	Sorting (IOI15_sorting)	C++14	100 / 100	723 ms	28112 KiB

sorting

#include "sorting.h"
#include <iostream>
#define s second
#define f first
#define pii pair<int,int>
using namespace std;
int idx[200005],a[200005];
pii d[600005];
 
int findSwapPairs(int N, int S[], int M, int x[], int y[], int p[], int q[]) {
    bool c = 1;
    for (int i=0;i<N;i++)
        if (S[i] != i) c=0;
    
    if (c) return 0;
    
    int l = 1,r = M,ans = 0;
    while(l <= r){
        int mid = (l+r)>>1;
        
        for (int i=0;i<N;i++){
            a[i] = S[i];
            idx[S[i]] = i;
        }
        
        for (int i = 0; i < mid; i++){
            swap(a[x[i]],a[y[i]]);
            swap(idx[a[x[i]]],idx[a[y[i]]]);
        }
       
        int cnt = 0;
        for (int i = 0; i < N; i++){
            if (a[i] == i) continue;
            
            d[cnt] = {a[i],i};
            cnt++;
            
            int ind = idx[i];
            swap(idx[a[i]],idx[i]);
            swap(a[i],a[ind]);
        }
        
        for (int i = cnt; i < M; i++)
          d[i] = {0,0};
        
        if (cnt <= mid){
            ans = mid;
            for (int i=0;i<N;i++){
                a[i] = S[i];
                idx[S[i]] = i;
            }
            
            for (int i = 0; i < M; i++){
                swap(a[x[i]],a[y[i]]);
                swap(idx[a[x[i]]],idx[a[y[i]]]);
                
                p[i] = d[i].f; q[i] = d[i].s;
                swap(idx[p[i]],idx[q[i]]);
                p[i] = idx[p[i]]; q[i] = idx[q[i]];
                swap(a[p[i]],a[q[i]]);
             }
            r = mid - 1;
        }
        else {
            l = mid + 1;
        }
    }
    
    return ans;
}

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