이 제출은 이전 버전의 oj.uz에서 채점하였습니다. 현재는 제출 당시와는 다른 서버에서 채점을 하기 때문에, 다시 제출하면 결과가 달라질 수도 있습니다.
#include <bits/stdc++.h>
#define ll long long
#define pb push_back
#define mp make_pair
#define ld long double
#define pll pair<ll,ll>
using namespace std;
const ld inf = 1e18;
const ll infll = 1e18;
const int maxn = 1100;
ll arr[maxn], pref[maxn];
ll dp[210][maxn], n, k;
ll parent[210][maxn];
struct cht {
struct line {
ll k, b; ld x;
ll val; bool isquery;
ll ind;
line (ll _k=0LL, ll _b=0LL, ll _ind=0) :
k(_k), b(_b), x(-inf), val(0), isquery(false), ind(_ind) { }
ll eval(ll x) const { return k*x+b; }
bool parallel(const line &l) const { return k == l.k; }
ld intersection(const line &l) const {
if(parallel(l)) return inf;
return (1.0*b - l.b) / (1.0*l.k - k);
}
bool operator <(const line &l) const {
if(l.isquery) return x < l.val;
else return k < l.k;
}
};
set<line>hull;
typedef set<line>::iterator iter;
bool cPrev(iter it) { return it != hull.begin(); }
bool cNext(iter it) { return it != hull.end() && next(it) != hull.end(); }
bool bad(const line &l1, const line &l2, const line &l3) {
return l1.intersection(l3) <= l1.intersection(l2);
}
bool bad(iter it) {
return cPrev(it) && cNext(it) && bad(*prev(it), *it, *next(it));
}
iter update(iter it) {
if(!cPrev(it)) return it;
line tmp(*it);
ld x = tmp.intersection(*prev(it));
tmp.x = x;
it = hull.erase(it);
return hull.insert(it, tmp);
}
void addline(ll k, ll b, ll ind) {
line l(k, b, ind);
iter it = hull.lower_bound(l);
if(it != hull.end() && it->parallel(l)) {
if(b > it->b) it = hull.erase(it);
else return;
}
it = hull.insert(it, l);
if(bad(it)) return (void) hull.erase(it);
while(cPrev(it) && bad(prev(it))) hull.erase(prev(it));
while(cNext(it) && bad(next(it))) hull.erase(next(it));
it = update(it);
if(cPrev(it)) update(prev(it));
if(cNext(it)) update(next(it));
}
pll query(ll x) {
if(hull.empty()) return mp(-infll, -1LL);
line tmp;
tmp.val = x; tmp.isquery = true;
iter it = --hull.lower_bound(tmp);
return mp(it->eval(x), it->ind);
}
};
int main() {
cin>>n>>k;
for(int i=1;i<=n;i++) {
cin>>arr[i];
pref[i] = pref[i-1] + arr[i];
}
for(int d=1;d<=k;d++) {
if(d == 1) {
for(int i=1;i<n;i++) {
dp[d][i] = pref[i] * (pref[n] - pref[i]);
}
continue;
}
cht ds;
for(int i=d;i<n;i++) {
// add info for state(d-1, i-1)
ds.addline(pref[i-1], dp[d-1][i-1] - pref[i-1]*pref[n], i-1);
pll curr = ds.query(pref[i]);
dp[d][i] = curr.first + pref[i]*pref[n] - pref[i] * pref[i];
parent[d][i] = curr.second;
}
}
ll result = -inf;
ll resultind = -1;
for(int i=k;i<n;i++) {
if(dp[k][i] > result) {
result = dp[k][i];
resultind = i;
}
}
cout<<result<<"\n";
vector<int>v;
for(int i=k;i>=1;i--) {
v.pb(resultind);
resultind = parent[i][resultind];
}
reverse(v.begin(), v.end());
for(int i:v) {
cout<<i<<" ";
} cout<<"\n";
}
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