Submission #670079

#	Time	Username	Problem	Language	Result	Execution time	Memory
670079		JooDdae	Split the sequence (APIO14_sequence)	C++17	71 / 100	63 ms	131072 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
using ll = long long;


int n, k, bt[100100][202];
ll s[100100], dp[100100][202];

array<ll, 3> t[202][100100];
int front[202], back[202];

bool check(int k, int a, int b, int c) {
    return (t[k][b][0]-t[k][a][0]) * (t[k][c][1]-t[k][a][1]) >= (t[k][c][0]-t[k][a][0]) * (t[k][b][1]-t[k][a][1]);
}


void f(int u, int k) {
    if(k == 0) return;
    f(bt[u][k], k-1);
    cout << u << " ";
}

int main(){
    cin.tie(0)->sync_with_stdio(0);
    cin >> n >> k;
    for(int i=1;i<=n;i++) cin >> s[i];

    for(int i=1;i<=n;i++) s[i] += s[i-1];

    for(int i=0;i<=k;i++) back[i] = -1;

    t[0][++back[0]] = {s[n], 0, 0};
    int mx = 0;

    for(int i=1;i<n;i++) {
        for(int j=min(i, k);j>=1;j--) {
            auto &f = front[j-1], &b = back[j-1];
            while(f+1 < b && check(j-1, b-2, b-1, b)) b--, t[j-1][b] = t[j-1][b+1];
            while(f < b && t[j-1][f][0]*s[i]+t[j-1][f][1] <= t[j-1][f+1][0]*s[i]+t[j-1][f+1][1]) f++;

            auto [X, Y, id] = t[j-1][f];
            dp[i][j] = X*s[i]+Y - s[i]*s[i], bt[i][j] = id;

            t[j][++back[j]] = {s[n]+s[i], dp[i][j] - s[n]*s[i], i};
        }
        if(dp[i][k] >= dp[mx][k]) mx = i;
    }

    cout << dp[mx][k] << "\n";
    f(mx, k);
}

• Subtask 1: 11 / 11
• Subtask 2: 11 / 11
• Subtask 3: 11 / 11
• Subtask 4: 17 / 17
• Subtask 5: 21 / 21
• Subtask 6: 0 / 29