Submission #1051458

#	Time	Username	Problem	Language	Result	Execution time	Memory
1051458		NeroZein	Fire (BOI24_fire)	C++17	0 / 100	1 ms	460 KiB

Main

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

#ifdef Nero
#include "Deb.h"
#else
#define debug(...)
#endif

int main() {
  ios::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, m;
  cin >> n >> m;
  vector<int> s(n), e(n);
  vector<int> normal;
  vector<int> non_normal;
  for (int i = 0; i < n; ++i) {
    cin >> s[i] >> e[i];
    if (s[i] <= e[i]) {
      normal.push_back(i);
    } else {
      non_normal.push_back(i); 
    }
  }
  sort(normal.begin(), normal.end(), [&](int i, int j) {
    return s[i] < s[j];
  });
  int res = 0;
  int lst = 0; 
  for (int i = 0, mx = 0; i < (int) normal.size(); ++i) {
    if (normal[i] > lst) {
      if (mx < s[normal[i]]) {
        break; 
      } else {
        res++; 
        lst = mx; 
        mx = e[normal[i]];
      }
    } else {
      mx = max(mx, e[normal[i]]);
    }
    if (i == (int) normal.size() - 1) {
      lst = mx; 
      res++;
    }
  }
  if (lst < m - 1) {
    res = n + 1; 
  }
  int ans = res; 
  for (int i = 0; i < (int) non_normal.size(); ++i) {
    vector<pair<int, int>> ranges;
    for (int j = 0; j < (int) non_normal.size(); ++j) {
      if (i != j) {
        ranges.push_back({0, e[non_normal[j]]});
      }
    }
    for (int j = 0; j < (int) normal.size(); ++j) {
      ranges.push_back({s[normal[j]], e[normal[j]]});
    }
    sort(ranges.begin(), ranges.end()); 
    res = 1;
    lst = e[non_normal[i]];
    debug(ranges); 
    for (int j = 0, mx = 0; j < (int) ranges.size(); ++j) {
      auto [l, r] = ranges[j];
      if (l > lst) {
        if (mx < l) {
          break;
        } else {
          res++;
          lst = mx; 
          mx = r; 
        }
      } else {
        mx = max(mx, r); 
      }
      if (j == (int) ranges.size() - 1) {
        lst = mx;
        res++; 
      }
    }
    if (lst < s[non_normal[i]]) {
      res = n + 1; 
    }
    ans = min(ans, res); 
  }
  if (ans == n + 1) {
    ans = -1; 
  }
  cout << ans << '\n';
  return 0;
}

• Subtask 1: 0 / 14
• Subtask 2: 0 / 17
• Subtask 3: 0 / 9
• Subtask 4: 0 / 13
• Subtask 5: 0 / 21
• Subtask 6: 0 / 26