1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
#include "message.h"
#include "kanapka.h"
#include <iostream>
#include <vector>

using namespace std;

using LL = long long;

int main()
{
  int n = GetN();
  int std_chunk_size = n / NumberOfNodes();
  int my_chunk_size;
  if (MyNodeId() == NumberOfNodes() - 1) {
    my_chunk_size = n - (NumberOfNodes() - 1) * std_chunk_size;
  } else {
    my_chunk_size = std_chunk_size;
  }

  LL my_sum = 0;
  LL beg = MyNodeId() * std_chunk_size;
  for (int i = beg; i < beg + my_chunk_size; ++i) {
    my_sum += GetTaste(i);
  }

  LL pref_sum = 0;
  LL best_pref = 0, best_suf = 0;
  LL both = 0;
  LL suf_sum = my_sum;
  for (int i = beg; i < beg + my_chunk_size; ++i) {
    LL taste = GetTaste(i);
    both = max(both, suf_sum + best_pref);
    pref_sum += taste;
    best_pref = max(best_pref, pref_sum);
    best_suf = max(best_suf, suf_sum);
    suf_sum -= taste;
  }
  both = max(both, best_pref);

  if (MyNodeId() != 0)
  {
    PutLL(0, my_sum);
    PutLL(0, best_pref);
    PutLL(0, best_suf);
    PutLL(0, both);
    Send(0);
    return 0;
  }

  int M = NumberOfNodes();
  vector<LL> sum(M), pref(M), suf(M), prefsuf(M);
  sum[0] = my_sum;
  pref[0] = best_pref;
  suf[0] = best_suf;
  prefsuf[0] = both;
  for (int node = 1; node < NumberOfNodes(); ++node)
  {
    Receive(node);
    sum[node] = GetLL(node);
    pref[node] = GetLL(node);
    suf[node] = GetLL(node);
    prefsuf[node] = GetLL(node);
  }
  LL sumall = 0;
  for (int i = 0; i < NumberOfNodes(); ++i) {
    sumall += sum[i];
  }
  best_pref = 0;
  LL sum_pref = 0;
  LL sum_suf = sumall;
  LL best = 0;
  for (int i = 0; i < NumberOfNodes(); ++i) {
    sum_suf -= sum[i];
    best = max(best, best_pref + suf[i] + sum_suf);
    best = max(best, sumall - sum[i] + prefsuf[i]);
    best_pref = max(best_pref, sum_pref + pref[i]);
    sum_pref += sum[i];
  }
  cout << best << endl;
  return 0;
}