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  1. #include <bits/stdc++.h>
  2. typedef long long ll;
  3. typedef long double ld;
  4. # define pb push_back
  5. # define FAST_CODE ios_base::sync_with_stdio(false); cin.tie(NULL);
  6. using namespace std;
  7.  
  8. ll triF(ll n) {
  9. 	return (sqrt(2*n + ld(0.25)) - ld(0.5));
  10. }
  11.  
  12. ll calc(ll n) {
  13. 	if(n % 2 == 0) {
  14. 		return ((n/2)*(n+1));
  15. 	}
  16.  
  17. 	return ((n+1)/2)*n;
  18. }
  19.  
  20. ll calc1(ll n) {
  21. 	if(n % 2 == 0) {
  22. 		return (n/2)*(n-1);
  23. 	}
  24.  
  25. 	return ((n-1)/2)*n;
  26. }
  27.  
  28. ll nearest(ll n) {
  29. 	ll k = ld(ld(1) + ld(sqrt(8*n + ld(1))))/ld(2);
  30. 	return calc1(k);
  31. }
  32.  
  33. int main() 
  34. {
  35. 	FAST_CODE;
  36. 	#ifndef ONLINE_JUDGE
  37. 		freopen("input.txt","r", stdin);
  38. 		freopen("output.txt","w", stdout);
  39. 	#endif
  40.  
  41. 	ll t;
  42. 	cin>>t;
  43. 	for(ll i=1; i<=t; ++i) {
  44. 		ll g;
  45. 		cin>>g;
  46. 		ll sumN = nearest(g);
  47. 		ll n = triF(g);
  48. 		ll ans = 0;
  49. 		for(ll i=n; i>=0; i--) {
  50. 			if((g - calc(i))%(i+1) == 0) {
  51. 				ans++;
  52. 				if((g - calc(i))/(i+1) == 0) {
  53. 					ans --;
  54. 				}
  55. 			}
  56. 		}
  57. 		cout<<"case #"<<i<<": "<<ans<<"\n";
  58.  
  59. 	}
  60. 	return 0;
  61. }
Success #stdin #stdout 0s 5604KB
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2
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case #1: 2
case #2: 4
https://ideone.com/rTABoc
language:
C++14 (gcc 8.3)
created:
2 years ago
visibility:
public

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