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119 | #include <bits/stdc++.h>
using namespace std;
const long long INF = 2000000000000000000;
const int MAX = 202;
long long N, M, P;
int cnt;
long long pref[MAX];
long long A[MAX];
long long dp[MAX][MAX][62];
long long dp_suf[MAX][62];
void input(){
cin.tie(NULL);
ios_base::sync_with_stdio(0);
cin >> N >> M;
for(int i = 0; i < N; i++){
cin >> A[i];
}
M++;
}
long long sum(int a, int b){
return pref[b + 1] - pref[a];
}
void make_pref(){
pref[0] = 0;
for(int i = 0; i < N; i++){
pref[i + 1] = pref[i] + A[i];
}
}
void process(){
make_pref();
cnt = 0;
P = 1;
while(P < M){
P *= 2;
cnt++;
}
for(int k = 0; k < cnt; k++){
for(int d = 1; d <= N; d++){
for(int a = 0; a <= N - d; a++){
int b = a + d - 1;
if(k == 0){
if(a == b){
dp[a][b][k] = max(A[a], (long long) 0);
} else if(b - a == 1){
dp[a][b][k] = A[b];
} else {
dp[a][b][k] = -INF;
}
} else {
long long RES = -INF;
RES = max(RES, dp[a][b][k - 1] + sum(a, b));
RES = max(RES, dp[a][b][k - 1]);
for(int c = a + 1; c <= b; c++){
RES = max(RES, dp[a][c - 1][k - 1] + dp[c][b][k - 1] + sum(c, b));
}
if(RES <= -INF/2) RES = -INF;
dp[a][b][k] = RES;
}
//cout << "a = " << a << " b = " << b << " k = " << k << " dp = " << dp[a][b][k] << endl;
}
}
}
for(int k = 0; k < cnt; k++){
long long M2 = M;
for(int x = 0; x < k; x++){
M2 /= 2;
}
if(M2 % 2 == 0 && k != cnt){
continue;
}
int prev = -1;
M2 = M;
for(int x = 0; x < k; x++){
if(M2 % 2 == 1){
prev = x;
}
M2 /= 2;
}
for(int a = 0; a < N; a++){
if(prev == -1){
if(k == 0){
if(a == N - 1){
dp_suf[a][k] = (long long) 0;
} else {
dp_suf[a][k] = -INF;
}
} else {
dp_suf[a][k] = dp[a][N - 1][k - 1];
}
} else {
long long RES = -INF;
RES = max(RES, dp_suf[a][prev] + sum(a, N - 1));
RES = max(RES, dp[a][N - 1][k - 1]);
for(int c = a + 1; c <= N - 1; c++){
RES = max(RES, dp[a][c - 1][k - 1] + dp_suf[c][prev] + sum(c, N - 1));
}
if(RES <= -INF/2) RES = -INF;
dp_suf[a][k] = RES;
}
//cout << "a = " << a << " k = " << k << " dp = " << dp_suf[a][k] << endl;
}
}
if(P == M){
cout << dp[0][N - 1][cnt - 1] << endl;
} else {
cout << dp_suf[0][cnt - 1] << endl;
}
}
int main(){
input();
process();
}
|