Submission #642231

#	Time	Username	Problem	Language	Result	Execution time	Memory
642231		christinelynn	Lasers (NOI19_lasers)	C++17	10 / 100	1100 ms	182344 KiB

lasers

#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("Ofast")
typedef long long ll;
// const ll mod = 1e9 + 7;
const ll MAXN = 1e6 + 5;
#define vi vector<int>
#define vll vector<ll>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define mp make_pair
#define pb push_back
#define lb lower_bound
#define ub upper_bound
#define fi first
#define sc second
#define endl '\n'
#define gl                        ios_base::sync_with_stdio(0);   cin.tie(0);                     cout.tie(0)

int main()
{
  gl;

  int l, r;
  cin >> l >> r;

  if (r == 1)
  {
    int x, a;
    cin >> x >> a;
    if (a <= l / 2)
      cout << 0 << endl;
    else
      cout << 2 * a - l << endl;
    return 0;
  }

  set<int> st;

  for (int i = 0; i < r; i++)
  {
    int x, a;
    cin >> x >> a;
    if (a <= l / 2)
      continue;
    for (int j = l - a + 1; j <= a; j++)
      st.insert(j);
  }

  cout << st.size() << endl;

  return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 0 / 14
• Subtask 3: 0 / 20
• Subtask 4: 0 / 21
• Subtask 5: 0 / 22
• Subtask 6: 0 / 13