Submission #815945

#	Time	Username	Problem	Language	Result	Execution time	Memory
815945		makanhulia	Lasers (NOI19_lasers)	C++17	21 / 100	45 ms	11104 KiB

lasers

#include <bits/stdc++.h>
using namespace std;

#define int long long

int presum[500005], start[500005], close[500005];

signed main() {
  int l, r, x, w;
  cin >> l >> r;
  for (int i = 1; i <= r; i++) {
    cin >> x;
    for (int j = 1; j <= x; j++) {
      cin >> w;
      presum[j] = presum[j-1] + w;
    }
    int gap = l - presum[x];
    for (int j = 1; j <= x; j++) {
      if (presum[j-1] + gap + 1 <= presum[j]) {
        start[presum[j-1] + gap + 1]++;
        close[presum[j]]++;
      }
    }
  }

  // Line Sweep

  int count = 0, save, ans = 0;
  for (int i = 1; i <= l; i++) {
    // cout << i << " " << start[i] << " " << close[i] << endl;
    if (start[i] == 0 and close[i] == 0) continue;

    if (count == 0) save = i;
    count += start[i];
    count -= close[i];
    if (count == 0) {
      ans += (i-save)+1;
    }
  }

  cout << ans << endl;
}

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