Submission #752783

#	Time	Username	Problem	Language	Result	Execution time	Memory
752783		jampm	Sorting (IOI15_sorting)	C++17	Compilation error	0 ms	0 KiB

sorting

#include "sorting.h"
#include <bits/stdc++.h>
using namespace std;
const int LOGN = 30;

int count_cycles(vector<int> & v, int n = 0) {
  n = (int)v.size(); int ans = 0;
  vector<bool> vis(n, false);
  for (int i = 0; i < n; i++) {
    if (vis[i]) continue;
    ans++;
    for (int j = v[i]; i != j; j = v[j]) vis[j] = true;
  }
  return ans;
}

int findswappairs(int n, int s[], int m, int x[], int y[], int p[], int q[]) {
  int ans = 0;
  for (int k = logn; k >= 0; k--) {
    if (ans + (1<<k) > m) continue;
    vector<int> v(n);
    for (int i = 0; i < n; i++) v[i] = s[i];
    for (int i = 0; i < ans + (1<<k); i++) {
      swap(v[x[i]], v[y[i]]);
    }
    if (count_cycles(v) + ans + (1<<k) < n) ans += (1<<k);
  }
  ans++;
  vector<int> v(n);
  for (int i = 0; i < n; i++) v[i] = s[i];
  for (int i = 0; i < ans; i++) {
    swap(v[x[i]], v[y[i]]);
  }
  vector<bool> vis(n, false);
  int cnt = 0;
  for (int i = 0; i < n; i++) {
    if (vis[i]) continue;
    p[cnt] = i, q[cnt] = vis[i]; cnt++;
    for (int j = v[i]; i != j; j = v[j]) {
      p[cnt] = j, q[cnt] = vis[j]; cnt++;
    }
  }
  return ans;
}

Compilation message (stderr)

sorting.cpp: In function 'int findswappairs(int, int*, int, int*, int*, int*, int*)':
sorting.cpp:19:16: error: 'logn' was not declared in this scope; did you mean 'logl'?
   19 |   for (int k = logn; k >= 0; k--) {
      |                ^~~~
      |                logl