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  1. #include<bits/stdc++.h>
  2. using namespace std;
  3. #define ll long long
  4. struct segtree{
  5. 	ll s, bs, bps, bss;
  6. }st[200020];
  7. ll a[50005];
  8. segtree merge(segtree A, segtree B)
  9. {
  10. 	segtree C;
  11. 	C.s=A.s+B.s;
  12. 	C.bps=max(A.bps, A.s+B.bps);
  13. 	C.bss=max(B.bss, B.s+A.bss);
  14. 	C.bs=max(max(B.s, A.s), A.bss+B.bps);
  15. 	return C;
  16. }
  17. void build(ll start, ll end, ll node)
  18. {
  19. 	if(start==end)
  20. 	{
  21. 		st[node].s=st[node].bps=st[node].bss=st[node].bs=a[start];
  22. 		return ;
  23. 	}
  24. 	ll mid=(start+end)/2;
  25. 	build(start, mid, 2*node);
  26. 	build(mid+1, end, 2*node+1);
  27. 	st[node]=merge(st[2*node], st[2*node+1]);
  28. }
  29. segtree query(ll start, ll end, ll l, ll r, ll node)
  30. {
  31. 	if(start>=l&&end<=r) return st[node];
  32. 	ll mid=(start+end)/2;
  33. 	if(mid>=r) return query(start, mid, l, r, 2*node);
  34. 	else if(mid<l) return query(mid+1, end, l, r, 2*node+1);
  35. 	else
  36. 	return merge(query(start, mid, l, r, 2*node), query(mid+1, end, l,r, 2*node+1));
  37. }
  38. int main()
  39. {
  40. 	ios_base::sync_with_stdio(false);
  41. 	cin.tie(0);
  42. 	cout.tie(0);
  43. 	ll n;
  44. 	cin>>n;
  45. 	for(ll i=1;i<=n;i++)
  46. 	cin>>a[i];
  47. 	build(1, n, 1);
  48. 	ll q;
  49. 	cin>>q;
  50. 	while(q--)
  51. 	{
  52. 		ll x, y;
  53. 		cin>>x>>y;
  54. 		segtree ss=query(1, n, x, y, 1);
  55. 		cout<<ss.bs<<endl;
  56. 	}
  57. }
Runtime error #stdin #stdout 0s 7744KB
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Standard input is empty
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Standard output is empty
https://ideone.com/GzT8G7
problem GSS1, based on SPOJ submission 25612463 (CPP14), 2020-03-24 05:17:05
language:
C++14 (gcc 8.3)
created:
4 years ago
visibility:
secret

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