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
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
#include<bits/stdc++.h>
#define FOR(i,a,b) for(int i=a;i<b;++i)
#define FOROP(i,a,b,op) for(int i=a;i<b;op)
#define FORD(i,a,b) for(int i=a;i>=b;--i)
#define PB push_back
#define FI first
#define SE second
#define umap unordered_map
#define uset unordered_set
#define vi vector<int>
#define vii vector<vi>
#define pii pair<int, int>
#define ALL(X) (X).begin(),(X).end()
#ifndef DEBUG
#define endl (char)10
#endif
using namespace std;
using ll = long long;

const ll INF = ((1LL << 62) + 44);

ll T[200];
ll P[201];

ll D[62][200][201];
ll N[62][200][201];
ll DT[62][200][201];
ll NT[62][200][201];
//dokladny (trymowany)
//najwyzej (trymowany)

int najw1(ll m){
    //kk - ile jedynek najwiecej ma liczba <= m
    ll p2 = 1;
    int kk = 0;
    while(p2 <= m){
        p2 = 2 * p2 + 1;
        kk++;
    }
    return kk;
}

int main () {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    int n;
    ll m;
    cin >> n >> m;
    FOR(i,0,n) cin >> T[i];
    if (m == 0){
        cout << 0 << endl;
        return 0;
    }
    int kk = najw1(m);
    if (n == 1){
        if (T[0] < 0){
            cout << 0 << endl;
            return 0;
        }
        cout << T[0] * kk << endl;
        return 0;
    }
    P[0] = 0;
    FOR(i,0,n) P[i + 1] = P[i] + T[i];
    FOR(i,0,n){
        D[0][i][i] = N[0][i][i] = DT[0][i][i] = NT[0][i][i] = 0;
        D[0][i][i+1] = N[0][i][i+1] = DT[0][i][i+1] = NT[0][i][i+1] = 0;
        FOR(j,i+2,n+1){
            D[0][i][j] = N[0][i][j] = DT[0][i][j] = NT[0][i][j] = -INF;
        }
    }
    FOR(k,1,kk+1){
        FOR(i,0,n){
            D[k][i][i] = 0;
            FOR(j,i+1,n+1)
                D[k][i][j] = (N[k - 1][i][j] == -INF ? -INF : N[k - 1][i][j] + P[j] - P[i]);
        }
        FOR(i,0,n){
            N[k][i][i] = 0;
            FOR(j,i+1,n+1){
                ll ans = max(N[k - 1][i][j], D[k][i][j]);
                FOR(x,i+1,j){
                    if (N[k - 1][i][x] != -INF && D[k][x][j] != -INF){
                        ans = max(ans, N[k - 1][i][x] + D[k][x][j]);
                    }
                }
                N[k][i][j] = ans;
            }
        }
    }
    ll bc = 1;
    FOR(k,1,kk+2){
        FOR(i,0,n){
            DT[k][i][i] = 0;
            if ((m & bc) != 0)
                FOR(j,i+1,n+1)
                    DT[k][i][j] = (NT[k - 1][i][j] == -INF ? -INF : NT[k - 1][i][j] + P[j] - P[i]);
            else
                FOR(j,i+1,n+1) DT[k][i][j] = -INF;
        }
        FOR(i,0,n){
            NT[k][i][i] = 0;
            if ((m & bc) != 0){
                FOR(j,i+1,n+1){
                    ll ans = max(N[k - 1][i][j], DT[k][i][j]);
                    FOR(x,i+1,j){
                        if (N[k - 1][i][x] != -INF && DT[k][x][j] != -INF){
                            ans = max(ans, N[k - 1][i][x] + DT[k][x][j]);
                        }
                    }
                    NT[k][i][j] = ans;
                }
            } else {
                FOR(j,i+1,n+1){
                    NT[k][i][j] = NT[k - 1][i][j];
                }
            }
        }
        bc *= 2;
    }
    cout << NT[kk+1][0][n] << endl;
/*
    FOR(k,0,kk+1){
        cout << "BITY: " << k << endl;
        FOR(i,0,n) FOR(j,i,n+1) cout << i << " " << j << " -> N=" << N[k][i][j] << endl;
    }
    FOR(k,0,kk+1){
        cout << "BITY: " << k << endl;
        FOR(i,0,n) FOR(j,i,n+1) cout << i << " " << j << " -> D=" << D[k][i][j] << endl;
    }*/
}