Submission #41878

#	Time	Username	Problem	Language	Result	Execution time	Memory
41878		funcsr	Sorting (IOI15_sorting)	C++14	0 / 100	13 ms	10112 KiB

sorting

#include "sorting.h"
#include <vector>
#include <iostream>
#include <algorithm>
#include <queue>
#include <cassert>
using namespace std;
#define rep(i, n) for (int i=0; i<(n); i++)
#define pb push_back
#define _1 first
#define _2 second
#define INF 1145141919
#define MOD 1000000007

bool used[200000];
vector<int> G[200000];
int findSwapPairs(int N, int S[], int M, int X[], int Y[], int P[], int Q[]) {
  if (is_sorted(S, S+N)) return 0;
  // subtask 1-4
  rep(i, N) used[i] = false;
  for (int i=M-1; i>=0; i--) {
    if (X[i] == Y[i]) continue;
    if (!used[X[i]]) {
      G[i].pb(X[i]);
      used[X[i]] = true;
    }
    if (!used[Y[i]]) {
      G[i].pb(Y[i]);
      used[Y[i]] = true;
    }
  }
  vector<int> ps;
  rep(i, M) {
    swap(S[X[i]], S[Y[i]]);
    //rep(i, N) cout<<S[i]<<",";cout<<"\n";
    for (int t : G[i]) if (S[t] != t) ps.pb(t);
    if (ps.empty()) {
      P[i] = Q[i] = 0;
      continue;
    }
    bool ok = false;
    rep(j, ps.size()) rep(k, j) {
      if (ok) break;
      int x = ps[j], y = ps[k];
      if (S[x] == y && x == S[y]) {
        ok = true;
        swap(S[x], S[y]);
        P[i] = x, Q[i] = y;
        break;
      }
    }
    if (!ok) {
      int x = ps[0], y = -1;
      rep(i, N) if (S[i] == x) y = i;
      swap(S[x], S[y]);
      P[i] = x, Q[i] = y;
    }
    vector<int> nps;
    for (int x : ps) if (S[x] != x) nps.pb(x);
    swap(ps, nps);
    if (is_sorted(S, S+N)) {
      M = i+1;
      break;
    }
    //cout<<"->"; rep(i, N) cout<<S[i]<<",";cout<<"\n";
  }
  rep(i, N) assert(S[i] == i);
  assert(ps.empty());
  return M;
}

Compilation message (stderr)

sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:8:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep(i, n) for (int i=0; i<(n); i++)
                                  ^
sorting.cpp:42:5: note: in expansion of macro 'rep'
     rep(j, ps.size()) rep(k, j) {
     ^~~
sorting.cpp:54:11: warning: declaration of 'i' shadows a previous local [-Wshadow]
       rep(i, N) if (S[i] == x) y = i;
           ^
sorting.cpp:8:28: note: in definition of macro 'rep'
 #define rep(i, n) for (int i=0; i<(n); i++)
                            ^
sorting.cpp:33:7: note: shadowed declaration is here
   rep(i, M) {
       ^
sorting.cpp:8:28: note: in definition of macro 'rep'
 #define rep(i, n) for (int i=0; i<(n); i++)
                            ^

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