Submission #405884

#	Time	Username	Problem	Language	Result	Execution time	Memory
405884		jk410	Sorting (IOI15_sorting)	C++17	20 / 100	2 ms	332 KiB

sorting

#include <bits/stdc++.h>
#include "sorting.h"
using namespace std;
int A[200000],tmp[200000],tmp_P[200000],tmp_Q[200000];
bool Visited[200000];
bool f(int N,int S[],int X[],int Y[],int k){
    for (int i=0; i<N; i++){
        tmp[i]=S[i];
        Visited[i]=false;
    }
    for (int i=0; i<k; i++){
        swap(tmp[X[i]],tmp[Y[i]]);
        tmp_P[i]=tmp_Q[i]=0;
    }
    int cnt=0;
    for (int i=0; i<N; i++){
        if (tmp[i]!=i&&!Visited[i]){
            Visited[i]=true;
            for (int j=tmp[i]; !Visited[j]; j=tmp[j]){
                Visited[j]=true;
                tmp_P[cnt]=j;
                tmp_Q[cnt]=tmp[j];
                cnt++;
                if (cnt>k)
                    return false;
            }
        }
    }
    return true;
}
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
    int ans=0,l=0,r=N;
    for (int i=0; i<N; i++)
        A[S[i]]=i;
    while (l<=r){
        int m=(l+r)>>1;
        if (f(N,S,X,Y,m)){
            ans=m;
            r=m-1;
        }
        else
            l=m+1;
    }
    for (int i=0; i<ans; i++){
        swap(A[S[X[i]]],A[S[Y[i]]]);
        swap(S[X[i]],S[Y[i]]);
        P[i]=A[tmp_P[i]];
        Q[i]=A[tmp_Q[i]];
        swap(S[A[tmp_P[i]]],S[A[tmp_Q[i]]]);
        swap(A[tmp_P[i]],A[tmp_Q[i]]);
    }
    return ans;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:31:39: warning: unused parameter 'M' [-Wunused-parameter]
   31 | int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
      |                                   ~~~~^

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