Submission #366984

#	Time	Username	Problem	Language	Result	Execution time	Memory
366984		rocks03	Split the sequence (APIO14_sequence)	C++14	100 / 100	960 ms	88684 KiB

sequence

//#pragma GCC target("avx2")
//#pragma GCC optimization("O3")
//#pragma GCC optimization("unroll-loops")
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define ff first
#define ss second
#define pb push_back
#define SZ(x) ((int)(x).size())
#define all(x) x.begin(), x.end()
#define rep(i, a, b) for(int i = (a); i < (b); i++)
#define per(i, a, b) for(int i = (a); i >= (b); i--)
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

const int MAXK = 200+10;
const int MAXN = 2e5+100;
int N, K, a[MAXN], opt[MAXN][MAXK];
ll pr[MAXN], dp[MAXN], dp2[MAXN];

struct line{
    ll m, q, i;
};

ll eval(line a, ll x){
    return (a.m * x + a.q);
}

bool pback(line a, line b, line c){
    return (a.q - b.q) * (c.m - b.m) <= (b.q - c.q) * (b.m - a.m);
}

void solve(){
    cin >> N >> K;
    rep(i, 1, N + 1){
        cin >> a[i];
        pr[i] = pr[i - 1] + a[i];
    }
    rep(k, 1, K + 1){
        deque<line> q;
        q.push_back({0, 0, 0});
        rep(i, 1, N + 1){
            while(SZ(q) > 1 && eval(q[0], pr[i]) <= eval(q[1], pr[i])){
                q.pop_front();
            }
            int j = q[0].i;
            dp2[i] = dp[j] + (pr[i] - pr[j]) * (pr[N] - pr[i]);
            opt[i][k] = j;
            line cur = {pr[i], dp[i] - pr[i] * pr[N], i};
            while(SZ(q) > 1 && pback(cur, q.back(), q[SZ(q) - 2])){
                q.pop_back();
            }
            q.push_back(cur);
        }
        swap(dp, dp2);
    }
    ll ans = -1; int ind = 0;
    per(i, N - 1, 1){
        if(dp[i] > ans){
            ans = dp[i], ind = i;
        }
    }
    cout << ans << "\n";
    per(k, K, 1){
        cout << ind << " ";
        ind = opt[ind][k];
    }
}

int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    solve();
    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