Submission #1269052

#	Time	Username	Problem	Language	Result	Execution time	Memory
1269052		vtnoo	Sorting (IOI15_sorting)	C++20	0 / 100	1 ms	328 KiB

sorting

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

const int MAXN=200000;
int E[MAXN], EF[MAXN], F[MAXN];

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]){
    for(int i=0;i<N;i++){
        E[S[i]]=i; //el item S[i] está en la posición i (permutacion actual)
    }
    auto S_=S;
    for(int i=0;i<M;i++){
        swap(S_[X[i]], S_[Y[i]]);
    }
    for(int i=0;i<N;i++){
        EF[S_[i]]=i;
        F[i]=E[S_[i]]; //el item S[i] va a terminar en la posicion i 
    }
    for(int i=0;i<M;i++)P[i]=Q[i]=0;
    int ans=0, cur=0;
    auto merge=[&](int a, int b, int aa, int bb){
        E[a]=bb;
        E[b]=aa;
        F[EF[a]]=bb;
        F[EF[b]]=aa;
    };
    for(int i=0;i<M;i++){ //a medida que avanzamos tenemoos que updatear los arrays
        int a=S[X[i]], b=S[Y[i]];
        swap(S[X[i]], S[Y[i]]);
        merge(a,b,X[i],Y[i]);
        if(E[cur]!=F[cur]){
            int a=cur, b=S[F[cur]];
            swap(S[E[cur]], S[F[cur]]);
            merge(a,b,E[cur],F[cur]);
            ans++;
        }
        cur++;
    }
    return ans;
}

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