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
#include <bits/stdc++.h>

using namespace std;

int main() {
#ifdef LOCAL
  freopen("input.txt", "r", stdin);
#endif
  ios::sync_with_stdio(false);
  cin.tie(0);
  int n;
  long long m;
  cin >> n >> m;
  vector<long long> a(n);
  for (int i = 0; i < n; ++i) {
    cin >> a[i];
  }
  vector<long long> s(n + 1);
  for (int i = 0; i < n; ++i) {
    s[i + 1] = s[i] + a[i];
  }
  vector<vector<long long>> foo(n, vector<long long>(n + 1, -(1ll << 60)));
  vector<vector<long long>> bar(n, vector<long long>(n + 1, -(1ll << 60)));
  for (int i = 0; i < n; ++i) {
    foo[i][i + 1] = bar[i][i + 1] = 0;
  }
  for (int d = 0; d < 60; ++d) {
    vector<vector<long long>> new_foo(n, vector<long long>(n + 1, -(1ll << 60)));
    vector<vector<long long>> new_bar(n, vector<long long>(n + 1, -(1ll << 60)));
    for (int i = 0; i < n; ++i) {
      for (int j = i + 1; j <= n; ++j) {
        for (int k = i; k <= j; ++k) {
          new_foo[i][j] = max(new_foo[i][j], (i < k ? foo[i][k] : 0) + (k < j ? foo[k][j] : 0) + s[j] - s[k]);
        }
      }
    }
    for (int i = 0; i < n; ++i) {
      for (int j = i + 1; j <= n; ++j) {
        if (m >> d & 1) {
          for (int k = i; k <= j; ++k) {
            new_bar[i][j] = max(new_bar[i][j], (i < k ? foo[i][k] : 0) + (k < j ? bar[k][j] : 0) + s[j] - s[k]);
          }
        } else {
          new_bar[i][j] = bar[i][j];
        }
      }
    }
    swap(foo, new_foo);
    swap(bar, new_bar);
  }
  cout << bar[0][n] << "\n";
  return 0;
}