Submission #1104825

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104825		VinhLuu	Railway Trip 2 (JOI22_ho_t4)	C++17	16 / 100	2067 ms	20176 KiB

Main

#include <bits/stdc++.h>
//#define int long long
#define ll long long
using namespace std;

const int N = 1e6 + 5;
const int oo = 1e9;

int n, m, k, q, a[N], b[N], S[N], T[N];

namespace sub2{
  int le[N], ri[N], f[N];
  void solve(){
    for(int i = 1; i <= n; i ++) le[i] = ri[i] = i;
    for(int i = 1; i <= m; i ++){
      if(a[i] < b[i]) for(int j = a[i]; j <= min(b[i] - 1, a[i] + k - 1); j ++){
        ri[j] = max(ri[j], b[i]);
      }else for(int j = a[i]; j >= max(a[i] - k + 1, b[i] + 1); j --){
        le[j] = min(le[j], b[i]);
      }
    }

//    for(int i = 1; i <= n; i ++) cerr << i << " " << le[i] << " " << ri[i] << " \n";

    for(int k = 1; k <= q; k ++){
      int x = S[k], y = T[k];
      queue<int> q;
      for(int i = 1; i <= n; i ++) f[i] = oo;
      for(int i = le[x]; i <= ri[x]; i ++){
        f[i] = 1;
        q.push(i);
      }
      int pl = le[x], pr = ri[x];
      f[x] = 0;
      while(!q.empty()){
        int u = q.front(); q.pop();
//        cerr << u << " " << f[u] << " g\n";
        if(le[u] < pl){
          for(int i = le[u]; i <= pl - 1; i ++){
            f[i] = f[u] + 1;
            q.push(i);
          }
          pl = le[u];
        }
        if(ri[u] > pr){
          for(int i = pr + 1; i <= ri[u]; i ++){
            f[i] = f[u] + 1;
            q.push(i);
          }
          pr = ri[u];
        }
      }
      if(f[y] == oo){
        cout << -1 << "\n";
        continue;
      }else cout << f[y] << "\n";
    }
  }
}

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 >> k >> m;
  for(int i = 1; i <= m; i ++) cin >> a[i] >> b[i];
  cin >> q;
  for(int i = 1; i <= q; i ++) cin >> S[i] >> T[i];
  sub2 :: solve();
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:65:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   65 |     freopen(task ".inp","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:66:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   66 |     freopen(task ".out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 8 / 8
• Subtask 3: 0 / 11
• Subtask 4: 0 / 25
• Subtask 5: 0 / 35
• Subtask 6: 0 / 13