Submission #1114343

#	Time	Username	Problem	Language	Result	Execution time	Memory
1114343		VinhLuu	Line Town (CCO23_day1problem3)	C++17	13 / 25	140 ms	40840 KiB

Main

#include <bits/stdc++.h>
#define int long long
#define ll long long
#define all(lpv) lpv.begin(), lpv.end()
#define fi first
#define se second
using namespace std;

typedef pair<int,int> pii;
const int N = 1e6 + 5;
const int oo = 1e16;
const int mod = 1e6 + 3;

int n, a[N], m, zero;

void add(int &x,int y){
  if(x == -1) x = y;
  else x = min(x, y);
}

int bit[N];

void update(int i,int val){
  for(; i <= n; i += i & -i) bit[i] += val;
}

int get(int i){
  int ret = 0;
  for(; i; i -= i & -i) ret += bit[i];
  return ret;
}

namespace Nlog{

  tuple<int,int,int> save[N];

  void solve(){
    int ans = -1;

    deque<int> col[2], rev[2];

    for(int i = 1; i <= n; i ++){
      if(a[i] == 0){ continue; }
      int x = abs(a[i]);
      if(i & 1){
        if(a[i] > 0) col[0].push_back(i);
        else col[1].push_back(i);
      }else{
        if(a[i] > 0) col[1].push_back(i);
        else col[0].push_back(i);
      }
      if((n - i + 1) & 1){
        if(a[i] > 0) rev[0].push_back(i);
        else rev[1].push_back(i);
      }else{
        if(a[i] > 0) rev[1].push_back(i);
        else rev[0].push_back(i);
      }
    }

    int le = 0, ri = 0;

    int tmp = n - zero;

    int ret = 0;

//    for(auto j : rev[0]) cerr << j << " ";
//    cerr << "\n";

    while(le < tmp){
      int nxt = ((le + 1) & 1);
      if(col[nxt].empty()) break;
      le++;
      int x = col[nxt].front();
//      cerr << nxt << " " << x << " r\n";
      ret += x - 1 - get(x - 1);
      update(x, 1);
//      cerr << x << " clear\n";
      if((n - x + 1) & 1){
        if(a[x] > 0){
//          cerr << "C0\n";
          rev[0].pop_front();
        }
        else{
//          cerr << " C1\n";
          rev[1].pop_front();
        }
      }else{
        if(a[x] > 0){
//          cerr << "C1\n";
          rev[1].pop_front();
        }
        else{
//          cerr << "C0\n";
          rev[0].pop_front();
        }
      }
      save[le] = {nxt, x, x - 1 - get(x - 1)};
      col[nxt].pop_front();
    }

//    cerr << le << " " << ret << " t\n";

    while(ri < tmp - le){
      int nxt = (((ri + 1) & 1) ^ 1);
      if(rev[nxt].empty()) break;
      ri++;
      int x = rev[nxt].back();
//      cerr << nxt << " " << x << " f\n";
      ret += n - x - (get(n) - get(x));
      update(x, 1);
      rev[nxt].pop_back();
    }

//    cerr << ri << " r\n";
//    cerr << " satrt\n";

    while(le >= 0){
      if(le + ri == tmp){
        add(ans, ret);
      }
      if(!le) break;
      int nxt, x, val; tie(nxt, x, val) = save[le];
      col[nxt].push_front(x);
      update(x, -1);
//      cerr << x << " rescue\n";
      ret -= x - 1 - get(x - 1);
      if((n - x + 1) & 1){
        if(a[x] > 0) rev[0].push_front(x);
        else rev[1].push_front(x);
      }else{
        if(a[x] > 0) rev[1].push_front(x);
        else rev[0].push_front(x);
      }
      le--;
//      cerr << le << " " << ret << " r\n";
      while(ri < tmp - le){
        int _right = (((ri + 1) & 1) ^ 1);
        if(rev[_right].empty()) break;
        int pos = rev[_right].back();
//        cerr << _right << " " << pos << " e\n";
        ri++;
        ret += (n - pos - (get(n) - get(pos)));
        update(pos, 1);
        rev[_right].pop_back();
      }
    }


    cout << ans;
  }
}

signed main(){
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  #define task "v"
  if(fopen(task ".inp","r")){
    freopen(task ".inp","r",stdin);
    freopen(task ".out","w",stdout);
  }
  cin >> n;
  vector<int> rrh;
  for(int i = 1; i <= n; i ++){
    cin >> a[i];
    zero += (a[i] == 0);
    if(a[i] != 0) rrh.push_back(abs(a[i]));
  }
  sort(all(rrh)); rrh.resize(unique(all(rrh)) - rrh.begin());
  m = (int)rrh.size();
  for(int i = 1; i <= n; i ++){
    if(a[i] == 0) continue;
    if(a[i] < 0) a[i] = -(lower_bound(all(rrh), abs(a[i])) - rrh.begin() + 1);
    else a[i] = lower_bound(all(rrh), abs(a[i])) - rrh.begin() + 1;
  }
  Nlog :: solve();
}
/*
5
0 -1 -1 0 1
*/

Compilation message (stderr)

Main.cpp: In function 'void Nlog::solve()':
Main.cpp:44:11: warning: unused variable 'x' [-Wunused-variable]
   44 |       int x = abs(a[i]);
      |           ^
Main.cpp: In function 'int main()':
Main.cpp:158:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  158 |     freopen(task ".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:159:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  159 |     freopen(task ".out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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