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
83
84
85
86
87
88
89
90
91
92
93
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
#define int long long

const int maxN = 256;
const int LG = 60;
const ll inf = 3e18;
ll dp[maxN][maxN][LG];
ll dp_[maxN][LG];
bool B[maxN][maxN][LG];
bool B_[maxN][LG];
ll sums[maxN];
int N, M, lg;


inline ll sum(int a, int b) {
    return sums[b] - sums[a - 1];
}


ll cnt(int a, int b, int l) {
    if (b - a + 1 > (1LL << l))
        return -inf;

    ll& res = dp[a][b][l];
    if (B[a][b][l])
        return res;

    B[a][b][l] = 1;
    if (l == 1) {
        res = sum(b, b);
        if (a == b && res < 0)
            res = 0;
        return res;
    }

    res = max(0LL, sum(a, b)) + cnt(a, b, l - 1);
    for (int i = a; i < b; ++i)
        res = max(res, cnt(a, i, l - 1) + cnt(i + 1, b, l - 1) + sum(i + 1, b));

    return res;
}


ll cnt_(int a, int l) {
    if (N - a + 1 > 1 + (((1LL << l) - 1) & M))
        return -inf;

    ll& res = dp_[a][l];
    if (B_[a][l])
        return res;

    B_[a][l] = 1;

    if (l == 1) {
        res = sum(N, N) * (M & 1);
        if (a == N && res < 0)
            res = 0;
        return res;
    }

    if ((M & (1LL << (l - 1))) == 0) {
        return res = cnt_(a, l - 1);
    }

    res = max(cnt(a, N, l - 1), cnt_(a, l - 1) + sum(a, N));
    for (int i = a; i < N; ++i)
        res = max(res, cnt(a, i, l - 1) + cnt_(i + 1, l - 1) + sum(i + 1, N));

    return res;
}

#undef int
int main() {
#define int long long
    scanf("%lld%lld", &N, &M);

    if (M == 0) {
        puts("0");
        return 0;
    }

    for (int i = 1; i <= N; ++i) {
        scanf("%lld", sums + i);
        sums[i] += sums[i - 1];
    }

    while ((1LL << lg) <= M)
        lg++;

    printf("%lld\n", cnt_(1, lg));
}