Submission #1135794

#	Time	Username	Problem	Language	Result	Execution time	Memory
1135794		huutuan	Strange Device (APIO19_strange_device)	C++20	100 / 100	291 ms	32720 KiB

strange_device

#include<bits/stdc++.h>

using namespace std;

#define int long long

const int N=1e6+10, inf=2e18;
int n, a, b;
int l[N], r[N];

int32_t main(){
   ios_base::sync_with_stdio(false);
   cin.tie(nullptr);
   cin >> n >> a >> b;
   for (int i=1; i<=n; ++i) cin >> l[i] >> r[i];
   int mod=a/__gcd(b+1, a);
   if (mod>inf/b){
      int ans=0;
      for (int i=1; i<=n; ++i) ans+=r[i]-l[i]+1;
      cout << ans << '\n';
      return 0;
   }
   mod*=b;
   vector<pair<int, int>> v;
   for (int i=1; i<=n; ++i){
      if (r[i]-l[i]+1>=mod){
         cout << mod << '\n';
         return 0;
      }
      l[i]%=mod; r[i]%=mod;
      if (l[i]>r[i]){
         v.emplace_back(l[i], mod-1);
         v.emplace_back(0, r[i]);
      }else{
         v.emplace_back(l[i], r[i]);
      }
   }
   sort(v.begin(), v.end());
   int ans=0;
   int ll=0, rr=-1;
   for (auto &i:v){
      if (rr+1>=i.first) rr=max(rr, i.second);
      else{
         ans+=rr-ll+1;
         ll=i.first, rr=i.second;
      }
   }
   cout << ans+rr-ll+1 << '\n';
   return 0;
}

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 5 / 5
• Subtask 5: 5 / 5
• Subtask 6: 20 / 20
• Subtask 7: 20 / 20
• Subtask 8: 30 / 30