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Submission #213019

# Submission time Handle Problem Language Result Execution time Memory
213019 2020-03-24T18:50:09 Z arman_ferdous Strange Device (APIO19_strange_device) C++17
10 / 100
 584 ms 17104 KB 
/* at time = 0, (x, y) = (0, 0)
 * we need to find minimum t > 0, such that (x, y) = 0 again ie. the cycle period.
 * now, y = 0 = t % B => t = K * B (for some integer K)
 * putting t in x's eqn and simplifying gives us a nice formula
 * K * (B + 1) % A = 0
 * from here it is easy to find K's value. 
 * answering queries are just merging intervals
 */

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

using ll = long long;
const double oo = 1e19;

vector<pair<ll,ll>> interval;

int main () {
  int n;
  ll A, B;
  scanf("%d %lld %lld", &n, &A, &B);

  int inf = 0, all = 0; ll sum = 0;
  ll g = __gcd(A, B + 1);
  ll K = A / g;
  ll T = K * B;
  
  if(K * 1.0 > oo / B * 1.0) inf = 1;
  while(n--) {
    ll l, r;
    scanf("%lld %lld", &l, &r);

    if(r - l + 1 >= T) {
      printf("%lld\n", T);
      return 0;
    } sum += r - l + 1;

    ll le = l % T;
    ll ri = r % T;
    if(le <= ri) {
      interval.push_back({le, ri});
    }
    else {
      interval.push_back({0, ri});
      interval.push_back({le, T - 1});
    }
  }

  if(inf) printf("%lld\n", sum);
  else {
    ll ans = 0;
    sort(interval.begin(), interval.end());
    for(int i = 0; i < (int)interval.size(); i++) {
      ans += interval[i].second - interval[i].first + 1;
      if(i) ans -= max(interval[i - 1].second - interval[i].first + 1, 0ll);
    }
    printf("%lld\n", ans);
  }
  return 0;
}

Compilation message

strange_device.cpp: In function 'int main()':
strange_device.cpp:23:16: warning: unused variable 'all' [-Wunused-variable]
   int inf = 0, all = 0; ll sum = 0;
                ^~~
strange_device.cpp:21:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %lld %lld", &n, &A, &B);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
strange_device.cpp:31:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld %lld", &l, &r);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Incorrect 10 ms 768 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #2
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 4 ms 256 KB Output is correct
3 Correct 4 ms 256 KB Output is correct
4 Correct 4 ms 384 KB Output is correct
5 Incorrect 4 ms 384 KB Output isn't correct

Subtask #3
0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Incorrect 5 ms 384 KB Output isn't correct
3 Halted 0 ms 0 KB -

Subtask #4
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 544 ms 16824 KB Output is correct
3 Correct 542 ms 16916 KB Output is correct
4 Correct 522 ms 16848 KB Output is correct

Subtask #5
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 544 ms 16824 KB Output is correct
3 Correct 542 ms 16916 KB Output is correct
4 Correct 522 ms 16848 KB Output is correct
5 Correct 5 ms 256 KB Output is correct
6 Correct 515 ms 16848 KB Output is correct
7 Correct 532 ms 16848 KB Output is correct
8 Correct 511 ms 16852 KB Output is correct
9 Correct 568 ms 17016 KB Output is correct

Subtask #6
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 544 ms 16824 KB Output is correct
3 Correct 542 ms 16916 KB Output is correct
4 Correct 522 ms 16848 KB Output is correct
5 Correct 4 ms 256 KB Output is correct
6 Correct 55 ms 2540 KB Output is correct
7 Correct 59 ms 2540 KB Output is correct
8 Correct 54 ms 2548 KB Output is correct
9 Correct 55 ms 2540 KB Output is correct
10 Correct 57 ms 2540 KB Output is correct
11 Correct 57 ms 2536 KB Output is correct
12 Correct 53 ms 2540 KB Output is correct
13 Correct 57 ms 2540 KB Output is correct
14 Correct 54 ms 2536 KB Output is correct
15 Incorrect 59 ms 2544 KB Output isn't correct
16 Halted 0 ms 0 KB -

Subtask #7
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 256 KB Output is correct
2 Correct 60 ms 2540 KB Output is correct
3 Correct 64 ms 2500 KB Output is correct
4 Correct 584 ms 17104 KB Output is correct
5 Correct 56 ms 2540 KB Output is correct
6 Correct 59 ms 2540 KB Output is correct
7 Correct 57 ms 2540 KB Output is correct
8 Correct 60 ms 2548 KB Output is correct
9 Correct 56 ms 2540 KB Output is correct
10 Correct 57 ms 2540 KB Output is correct
11 Correct 58 ms 2540 KB Output is correct
12 Correct 52 ms 2540 KB Output is correct
13 Correct 60 ms 2540 KB Output is correct
14 Incorrect 563 ms 16828 KB Output isn't correct
15 Halted 0 ms 0 KB -

Subtask #8
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 4 ms 384 KB Output is correct
2 Incorrect 10 ms 768 KB Output isn't correct
3 Halted 0 ms 0 KB -