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  1. #include <bits/stdc++.h>
  2. using namespace std; 
  3.  
  4. #define fst first
  5. #define snd second 
  6.  
  7. typedef long long ll; 
  8. typedef pair<int, int> ii; 
  9.  
  10. const ll LINF = (ll)1e18; 
  11. const int INF = (int)1e9;
  12.  
  13. const int N = (int)1e6 + 5;   
  14.  
  15. int n; 
  16. int a[N]; 
  17. ll sum[N]; 
  18.  
  19. bool isPrime[N]; 
  20.  
  21. void sieve() {
  22. 	for (int i = 2; i < N; i++) isPrime[i] = true;  
  23.  
  24. 	for (int i = 2; i * i < N; i++) {
  25. 		if (isPrime[i]) {
  26. 			for (int j = i * i; j < N; j += i) isPrime[j] = false; 
  27. 		}
  28. 	}
  29. }
  30.  
  31. int main() {
  32. 	ios::sync_with_stdio(0); 
  33. 	cin.tie(0); 
  34. 	cin >> n; 
  35. 	for (int i = 1; i <= n; i++) {
  36. 		cin >> a[i]; 
  37. 		sum[i] = sum[i - 1] + a[i]; 
  38. 	}
  39.  
  40. 	sieve();  
  41.  
  42. 	ll ans = -LINF;  
  43. 	ll min_sum_l = LINF; 
  44. 	for (int r = 2; r <= n; r++) {
  45. 		if (isPrime[r]) {
  46. 			ll max_sum = sum[r] - min_sum_l;    
  47. 			ans = max(ans, max_sum);   
  48. 			min_sum_l = min(min_sum_l, sum[r - 1]); 
  49. 		}
  50. 	}
  51.  
  52. 	cout << ans << '\n';
  53. }
  54.  
Success #stdin #stdout 0.01s 6524KB
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https://ideone.com/DewSp4
language:
C++14 (gcc 8.3)
created:
1 year ago
visibility:
secret

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