Submission #1284122

#	Time	Username	Problem	Language	Result	Execution time	Memory
1284122		Johan	Money (IZhO17_money)	C++20	100 / 100	274 ms	8228 KiB

money

#include<bits/stdc++.h>
using namespace std;
struct BIT {
  int n;
  vector < int > fw;  
  BIT (int n) : n(n){
    fw.assign(n + 1, 0);
  }
  void upd(int idx, int val){
    while(idx <= n){
      fw[idx] += val;
      idx += (idx & -idx);
    }
  }
  int ask(int idx){
    int rs = 0;
    while(idx > 0){
      rs += fw[idx];
      idx -= (idx & -idx);
    }
    return rs;
  }
  int get(int l, int r){
    if(l > r)return 0;
    return ask(r) - ask(l - 1);
  }
};
int main(){
  // freopen("input.txt", "r", stdin);
  // freopen("output.txt", "w", stdout);
  int n;
  cin >> n;
  int a[n + 1], idx = 1;
  for(int i = 1; i <= n; i++)
    cin >> a[i];
  if(is_sorted(a + 1, a + n + 1) == true){
    cout << 1 << endl;
    return 0;
  }
  BIT fw(1e6);
  fw.upd(a[1], 1);
  for(int i = 2; i <= n; i++){
    if(a[i] < a[i - 1])break;
    if(!fw.get(a[i], a[i]))fw.upd(a[i], 1);
    idx = i;
  }
  int ans = 1;
  vector < int > cur{a[idx + 1]};
  for(int i = idx + 2; i <= n; i++){
    if(a[i] < a[i - 1]){
      for(auto j : cur){
        if(!fw.get(j, j))
          fw.upd(j, 1);
      }
      cur = {a[i]};
      ans++;
      continue;
    }
    cur.push_back(a[i]);
    int chk = fw.get(cur[0] + 1, cur.back() - 1);
    if(chk > 0){
      cur.pop_back();
      for(auto j : cur){
        if(!fw.get(j, j))
          fw.upd(j, 1);
      }
      cur = {a[i]};
      ans++;
    }
  }
  cout << ans + 1 << endl;
}
 

• Subtask 1: 9 / 9
• Subtask 2: 16 / 16
• Subtask 3: 20 / 20
• Subtask 4: 55 / 55