Submission #1112880

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112880		ntdaccode	Line Town (CCO23_day1problem3)	C++17	0 / 25	1 ms	336 KiB

Main

#include<bits/stdc++.h>
#define fori(i,a,b) for(int i=a;i<=b;i++)
#define int long long
#define pb push_back

using namespace std;
typedef pair<int,int> ii;
typedef tuple<int,int,int> tp;
const int M=1e6+10;
const int N=5e5+10;
const int mod=1e9+7;
int n,f[N],a[N],b[N],g[N];
void sub1()
{
  int kq = 1e9;
  for(int pos = 0;pos <= n; pos++) {
    for(int i = 1;i <= n; i++) b[i] = a[i];
    bool ok = 0;
    int  res = 0;
    //
    for(int i = 1;i <= pos ; i++) {
      if(b[i] == 1) {
        if(b[i + 1] == 1 && i != pos) i++,res++;
        else ok = 1;
      }
    }
    for(int i = pos + 1;i <= n;i++) {
      if(b[i] == -1) {
        if(b[i + 1] == -1 && i != n) i++,res++;
        else ok = 1;
      }
    }
    if(ok == 0) kq = min(kq,res);
  }
  cout << (kq == 1e9 ? -1 : kq);
}
void sub2()
{
  int kq = 1e9;
  f[0] = g[n+1] = 0;
  f[1] = (a[1] == -1 ? 0 : 1e9);
  g[n] = (a[n] ==  1 ? 0 : 1e9);
  for(int i = 2;i <= n; i++) {
    if(a[i] == 1)
    {
      if(a[i-1] == 1) f[i] = f[i - 2] + 1;
      else f[i] = 1e9;
    }
    else f[i] = f[i - 1];
  }
  for(int i = n - 1;i != 0;i--) {
      if(a[i] == -1)
      {
        if(a[i+1] == -1) g[i] = g[i + 2] + 1;
        else g[i] = 1e9;
      }
      else g[i] = g[i + 1];
  }
  for(int i = 0;i <= n;i++) kq = min(kq,f[i] + g[i+1]);
  cout << (kq == 1e9 ? -1 : kq);
}
int32_t main()
{
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  if(fopen("1.inp","r"))
  {
    freopen("1.inp","r",stdin);
    freopen("1.out","w",stdout);
  }
  #define task ""
  if(fopen(task".inp","r"))
  {
    freopen(task".inp","r",stdin);
    freopen(task".out","w",stdout);
  }

  cin >> n;
  for(int i = 1;i <= n; i++) cin >> a[i];
  if(n <= 2000) sub1();
  else sub2();
  //sub2();

}

Compilation message (stderr)

Main.cpp: In function 'int32_t main()':
Main.cpp:69:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   69 |     freopen("1.inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~
Main.cpp:70:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   70 |     freopen("1.out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~
Main.cpp:75:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |     freopen(task".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
Main.cpp:76:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |     freopen(task".out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 3
• Subtask 2: 0 / 3
• Subtask 3: 0 / 3
• Subtask 4: 0 / 4
• Subtask 5: 0 / 4
• Subtask 6: 0 / 3
• Subtask 7: 0 / 2
• Subtask 8: 0 / 3