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  1. #include <iostream>
  2. #include <cmath>
  3.  
  4. using namespace std;
  5.  
  6. #define FOR(i,a,b) for(int i=a; i<=b; i++)
  7. #define MOD 1000000007
  8.  
  9. typedef long long LL;
  10.  
  11. int main()
  12. {
  13. 	double A,B;
  14. 	LL a,b;
  15.  
  16. 	cin>>A>>B;
  17.  
  18. 	a = ceil(A);
  19. 	b = floor(B);
  20.  
  21.      LL sb = b * (b + 1) / 2 % (MOD) * (2 * b + 1) / 3;
  22. 	 LL sa = a * (a - 1) / 2 % (MOD) * (2 * a - 1) / 3;
  23.  
  24. 	if (sb < sa) sb += MOD;
  25.     	cout<<((sb - sa) % MOD)<<endl;
  26.  
  27.  
  28. 	return 0;
  29. }
Success #stdin #stdout 0s 3460KB
comments (?)
stdin 
0.1 1000000000
stdout 
999999916
https://ideone.com/3gyNmz
TITO2 - Tính tổng 2 (OLP Không Chuyên 2014) [ACCEPTED]
language:
C++ (gcc 8.3)
created:
8 years ago
visibility:
secret

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