Submission #1150182

#	Time	Username	Problem	Language	Result	Execution time	Memory
1150182		nai0610	Split the sequence (APIO14_sequence)	C++20	100 / 100	626 ms	85348 KiB

sequence

#include <bits/stdc++.h>
#define ll int64_t
#define ld long double
using namespace std;
// 
const int maxn =1e5+5;
const int mod = 1e9+7; // 998244353,1610612741
const ll inf = 1e18;
const ld pi = atan(1.0L)*4;
int n,K;
int pre[205][maxn];
ll a[maxn],s[maxn];
struct CHT{
	vector<ll> M,C;
	vector<int> pos;
	int id=0,sz=0;
	bool bad(int l1,int l2,int l3) {
		return (C[l3]-C[l1])*(M[l1]-M[l2])<=(C[l2]-C[l1])*(M[l1]-M[l3]);
	}
	void add(ll a,ll b,int i) {
		M.push_back(a);C.push_back(b);
		pos.push_back(i);
		sz++;
	    while (sz>=3&&bad(sz-3,sz-2,sz-1)){
	    	sz--;
	        M.erase(M.end()-2);
	        C.erase(C.end()-2);
	        pos.erase(pos.end()-2);
	    }
	}
	pair<ll,int> get(ll x) {
	    if (id>=sz) id=sz-1;
	    while (id<sz-1&&M[id+1]*x+C[id+1]>M[id]*x+C[id]) id++;
	    return {M[id]*x+C[id],pos[id]};
	}
};
int main() {
    // freopen("../input.inp","r",stdin);
    // freopen("output.out","w",stdout);
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    clock_t start,end;
	start=clock();
	cin >>n>>K;
	K++;
	for (int i=1;i<=n;i++) cin >>a[i],s[i]=s[i-1]+a[i];
	vector<ll> f(n+1);
	for (int i=1;i<=n;i++) f[i]=s[i]*s[i];
	for (int k=2;k<=K;k++) {
		vector<ll> g(n+1);
		CHT cht;
		for (int i=k;i<=n;i++) {
			cht.add(2*s[i-1],-s[i-1]*s[i-1]-f[i-1],i);
			auto p=cht.get(s[i]);
			g[i]=-p.first+s[i]*s[i];
			pre[k][i]=p.second;
		}
		swap(f,g);
	}
	cout <<(s[n]*s[n]-f[n])/2<<'\n';
	int i=n;
	vector<int> v;
	while (i>0) {
		i=pre[K--][i]-1;
		if (i>0) v.push_back(i);
	}
	sort(v.begin(),v.end());
	for (auto i:v) cout <<i<<" ";
	end=clock();
	ld dur=(ld)(end-start)/(ld)(CLOCKS_PER_SEC)*(1000.0L);
	cerr<<dur<<'\n';
    return 0;
}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 29 / 29