Submission #58360

#	Time	Username	Problem	Language	Result	Execution time	Memory
58360		E869120	Sorting (IOI15_sorting)	C++14	0 / 100	5 ms	640 KiB

sorting

#include <iostream>
#include <vector>
#include <algorithm>
#include <cassert>
using namespace std;

int N, S[200009], M, X[200009], Y[200009], A[200009], B[200009], C[200009];

vector<pair<int, int>> solve(int pos) {
	// 第一部
	for (int i = 0; i < N; i++) A[i] = S[i];
	for (int i = 0; i < pos; i++) swap(A[X[i]], A[Y[i]]);
	vector<pair<int, int>>Z;
	for (int i = 0; i < N; i++) {
		int s1 = 0;
		for (int j = 0; j < N; j++) { if (A[j] == i) s1 = j; }
		swap(A[i], A[s1]); Z.push_back(make_pair(i, s1));
	}
	if (Z.size() > pos) return vector<pair<int, int>>{make_pair(-1, -1)};
	while (Z.size() < pos) Z.push_back(make_pair(0, 0));

	// 第二部
	vector<pair<int, int>>ZZ;
	for (int i = 0; i < N; i++) { A[i] = S[i]; B[S[i]] = i; C[i] = S[i]; }
	for (int i = 0; i < pos; i++) swap(C[X[i]], C[Y[i]]);
	for (int i = 0; i < pos; i++) {
		swap(A[X[i]], A[Y[i]]); swap(B[A[X[i]]], B[A[Y[i]]]);
		int num1 = C[Z[i].first], num2 = C[Z[i].second];
		int p1 = B[num1], p2 = B[num2];
		ZZ.push_back(make_pair(p1, p2));
		swap(A[p1], A[p2]); swap(B[A[p1]], B[A[p2]]); swap(C[Z[i].first], C[Z[i].second]);
	}
	return ZZ;
}

bool check(vector<pair<int, int>>res) {
	for (int i = 0; i < N; i++) A[i] = S[i];
	for (int i = 0; i < res.size(); i++) {
		swap(A[X[i]], A[Y[i]]);
		swap(A[res[i].first], A[res[i].second]);
	}
	for (int i = 0; i < N; i++) { if (A[i] != i) return false; }
	return true;
}

int findSwapPairs(int NN, int SS[], int MM, int XX[], int YY[], int P[], int Q[]) {
	N = NN; M = MM;
	for (int i = 0; i < NN; i++) S[i] = SS[i];
	for (int i = 0; i < MM; i++) { X[i] = XX[i]; Y[i] = YY[i]; }

	/*int L = 0, R = M + 1, M_; vector<pair<int, int>>ret;
	for (int i = 0; i < 20; i++) {
		M_ = (L + R) / 2;
		vector<pair<int, int>> z = solve(M_);
		if (z == vector<pair<int, int>>{make_pair(-1, -1)}) L = M_;
		else { R = M_; ret = z; }
	}*/
	vector<pair<int, int>>ret = solve(M);
	for (int i = 0; i < ret.size(); i++) { P[i] = ret[i].first; Q[i] = ret[i].second; }

	if (check(ret) == false) { assert(false); }
	return ret.size();
}

Compilation message (stderr)

sorting.cpp: In function 'std::vector<std::pair<int, int> > solve(int)':
sorting.cpp:19:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  if (Z.size() > pos) return vector<pair<int, int>>{make_pair(-1, -1)};
      ~~~~~~~~~^~~~~
sorting.cpp:20:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while (Z.size() < pos) Z.push_back(make_pair(0, 0));
         ~~~~~~~~~^~~~~
sorting.cpp: In function 'bool check(std::vector<std::pair<int, int> >)':
sorting.cpp:38:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < res.size(); i++) {
                  ~~^~~~~~~~~~~~
sorting.cpp: In function 'int findSwapPairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:59:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (int i = 0; i < ret.size(); i++) { P[i] = ret[i].first; Q[i] = ret[i].second; }
                  ~~^~~~~~~~~~~~
sorting.cpp:62:17: warning: conversion to 'int' from 'std::vector<std::pair<int, int> >::size_type {aka long unsigned int}' may alter its value [-Wconversion]
  return ret.size();
         ~~~~~~~~^~

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