| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 791355 | trucmai | Feast (NOI19_feast) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
//i_love_aisukiuwu
#pragma GCC optimize("Ofast,no-stack-protector,fast-math,unroll-loops,tree-vectorize")
#pragma GCC target("arch=skylake")
#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include "/home/trucmai/.vim/tools.h"
#define debug(x...) cerr << "\e[91m"<<__func__<<":"<<__LINE__<<" [" << #x << "] = ["; _print(x); cerr << "\e[39m" << endl;
#else
#define debug(x...)
#endif
void open(){
if(fopen("i.inp","r")){
freopen("i.inp","r",stdin);
freopen("o.out","w",stdout);
}
}
#define ll long long
#define all(a) (a).begin(), (a).end()
#define vi vector<ll>
#define pi pair<ll,ll>
#define pii pair<ll,pair<ll,ll>>
#define fi first
#define se second
#define gcd __gcd
#define mset(a,v) memset(a, v, sizeof(a))
#define endl '\n'
#define spc " "
const int MN1 = 1e6 + 5,MN2 = 2e3 + 5,LOG = 27;
const ll MOD = 1e9 + 7,INF = 1e9;
ll n,k,a[MN1],dp[MN2][MN2][2];
/*
dp[i][j][k(0\1)] la max sum tai vi tri i,segment j va state k
k = 0:
dp[i][j][0] = max(dp[i-1][j][0],dp[i-1][j][1] + a[j])
k = 1:
dp[i][j][1] = max(dp[i-1][j-1][0],dp[i-1][j][1] + a[j])
*/
void solve(){
cin>>n>>k; ll cnt = 0;
for(ll i = 1;i <= n;++i){
cin>>a[i];
if(a[i] < 0) ++cnt;
}
if(cnt == 0){
ll res = 0;
for(ll i = 1; i <= n;++i) res += a[i];
cout<<res<<endl;
}
else if(cnt == 1){
ll left = 0, right = 0, flag = 0, pos = -1,res = 0;
for(int i = 1; i <= n; i++){
if(a[i] < 0){
pos = i;
flag = 1;
continue;
}
else if(flag == 0) left += a[i];
else right += a[i];
}
debug(left,right);
if(k >= 2) res = left + right;
else if(k == 1) res = max(max(left,right), left + right + a[pos]);
cout<<res<<endl;
}
else if(k == 1){
ll help = 0,res = 0;
for(int i = 1; i <= n; i++){
help += a[i];
if(res < help) res = help;
if(help < 0) help = 0;
}
cout<<res<<endl;
}
else{
mset(dp,-1);
auto f=[&](ll i,ll j,bool state,auto &&f)->ll{
if(i > n || j > k) return 0;
ll &res = dp[i][j][state];
if(res != -1) return res;
res = 0;
res = max(res,f(i+1,j,1,f) + a[i]);
if(!state) res = max(res,f(i+1,j,0,f));
else if(j + 1 < k && state) res = max(res,f(i+1,j+1,0,f));
return res;
};
cout<<f(1,0,0,f)<<endl;
}
}
signed main(){
cin.tie(0) -> sync_with_stdio(0);
open();
ll t = 1; //cin>>t;
while(t--) solve();
#ifdef LOCAL
cerr << endl << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << " s.\n";
#endif
}