Submission #1018570

#	Time	Username	Problem	Language	Result	Execution time	Memory
1018570		huutuan	Sorting (IOI15_sorting)	C++14	74 / 100	1052 ms	23380 KiB

sorting

#include "sorting.h"

#include <bits/stdc++.h>

using namespace std;

int a[200010], pos[200010], s[200010];

int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
   if (is_sorted(S, S+N)) return 0;
   for (int _=0; _<M; ++_){
      for (int i=0; i<N; ++i) s[i]=S[i];
      for (int i=0; i<N; ++i) pos[s[i]]=i;
      iota(a, a+N, 0);
      for (int i=_; i>=0; --i) swap(a[X[i]], a[Y[i]]);
      set<int> st;
      for (int i=0; i<N; ++i) if (a[i]!=s[i]) st.insert(i);
      for (int i=0; i<=_; ++i){
         P[i]=Q[i]=0;
         swap(a[X[i]], a[Y[i]]);
         swap(s[X[i]], s[Y[i]]);
         pos[s[X[i]]]=X[i];
         pos[s[Y[i]]]=Y[i];
         st.erase(X[i]); st.erase(Y[i]);
         if (a[X[i]]!=s[X[i]]) st.insert(X[i]);
         if (a[Y[i]]!=s[Y[i]]) st.insert(Y[i]);
         // if (is_sorted(s, s+N)){
         //    return i+1;
         // }
         if (st.size()){
            int j=*st.begin(); st.erase(st.begin());
            int k=pos[a[j]];
            P[i]=j, Q[i]=k;
         }
         swap(s[P[i]], s[Q[i]]);
         pos[s[P[i]]]=P[i];
         pos[s[Q[i]]]=Q[i];
         st.erase(P[i]); st.erase(Q[i]);
         if (a[P[i]]!=s[P[i]]) st.insert(P[i]);
         if (a[Q[i]]!=s[Q[i]]) st.insert(Q[i]);
         // if (is_sorted(s, s+N)){
         //    return i+1;
         // }
      }
      if (is_sorted(s, s+N)) return _+1;
   }
   return -1;
}

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