Submission #438847

# Submission time Handle Problem Language Result Execution time Memory
438847 2021-06-28T17:51:30 Z blue Split the sequence (APIO14_sequence) C++17
100 / 100
870 ms 82996 KB
#include <iostream>
#include <deque>
using namespace std;

/*
dp[c][i] = min{dp[c-1][j] + (a_sum[i] - a_sum[j]) * a_sum[j] | 1 <= j < i}
         = min{a_sum[j] * a_sum[i]   +   dp[c-1][j] - a_sum[j]^2    | 1 <= j < i}
                 A        * X           +        B
*/

struct line
{
    long long a;
    long long b;
    int i;

    long long eval(long long x)
    {
        return a*x + b;
    }
};

long long sq(long long x)
{
    return x*x;
}


bool intersect_comp(line l1, line l2, line r1, line r2)
{
    //intersect(l1, l2) <=> l1.a * x + l1.b == l2.a * x + l2.b
    /*
        xL = (l2.b - l1.b)/(l1.a - l2.a)
        xR = (r2.b - r1.b)/(r1.a - r2.a)

        xL < xR <=> ()
    */

    return (l2.b - l1.b)*(r1.a - r2.a) < (r2.b - r1.b)*(l1.a - l2.a);
}



int main()
{
    int n, k;
    cin >> n >> k;

    long long a[n+1], a_sum[n+1];
    a_sum[0] = 0;
    for(int i = 1; i <= n; i++)
    {
        cin >> a[i];
        a_sum[i] = a[i] + a_sum[i-1];
    }

    long long* dp[k+1];
    int* prev[k+1];

    dp[0] = new long long[n+1];
    dp[1] = new long long[n+1];

    prev[0] = new int[n+1];
    prev[1] = new int[n+1];

    for(int x = 2; x <= k; x++)
    {
        dp[x] = dp[x-2];
        prev[x] = new int[n+1];
    }

    for(int i = 0; i <= n; i++)
    {
        dp[0][i] = 0;
        prev[0][i] = 0;
    }

    for(int c = 1; c <= k; c++)
    {
        prev[c][1] = 0;
        dp[c][1] = 0;

        deque<line> cht;
        cht.push_back(line{a_sum[1], dp[c-1][1] - sq(a_sum[1]), 1});
        for(int i = 2; i <= n; i++)
        {
            while(cht.size() > 1 && cht[0].eval(a_sum[i]) <= cht[1].eval(a_sum[i]))
                cht.pop_front();

            dp[c][i] = cht[0].eval(a_sum[i]);
            prev[c][i] = cht[0].i;

            line new_line = line{a_sum[i], dp[c-1][i] - sq(a_sum[i]), i};
            while(cht.size() > 1 && !intersect_comp(cht[cht.size()-2], cht[cht.size()-1],  cht.back(), new_line))
                cht.pop_back();

            cht.push_back(new_line);
        }
    }


    cout << dp[k][n] << '\n';
    int x = n, y = k;
    for(y = k; y >= 1; y--)
    {
        cout << prev[y][x] << ' ';
        x = prev[y][x];
    }
    cout << '\n';
}
# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB contestant found the optimal answer: 108 == 108
2 Correct 1 ms 204 KB contestant found the optimal answer: 999 == 999
3 Correct 1 ms 204 KB contestant found the optimal answer: 0 == 0
4 Correct 1 ms 204 KB contestant found the optimal answer: 1542524 == 1542524
5 Correct 1 ms 204 KB contestant found the optimal answer: 4500000000 == 4500000000
6 Correct 1 ms 204 KB contestant found the optimal answer: 1 == 1
7 Correct 1 ms 288 KB contestant found the optimal answer: 1 == 1
8 Correct 1 ms 204 KB contestant found the optimal answer: 1 == 1
9 Correct 1 ms 204 KB contestant found the optimal answer: 100400096 == 100400096
10 Correct 1 ms 204 KB contestant found the optimal answer: 900320000 == 900320000
11 Correct 1 ms 204 KB contestant found the optimal answer: 3698080248 == 3698080248
12 Correct 1 ms 204 KB contestant found the optimal answer: 3200320000 == 3200320000
13 Correct 1 ms 204 KB contestant found the optimal answer: 140072 == 140072
14 Correct 1 ms 204 KB contestant found the optimal answer: 376041456 == 376041456
15 Correct 1 ms 204 KB contestant found the optimal answer: 805 == 805
16 Correct 1 ms 204 KB contestant found the optimal answer: 900189994 == 900189994
17 Correct 1 ms 204 KB contestant found the optimal answer: 999919994 == 999919994
# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB contestant found the optimal answer: 1093956 == 1093956
2 Correct 1 ms 204 KB contestant found the optimal answer: 302460000 == 302460000
3 Correct 1 ms 204 KB contestant found the optimal answer: 122453454361 == 122453454361
4 Correct 1 ms 204 KB contestant found the optimal answer: 93663683509 == 93663683509
5 Correct 1 ms 204 KB contestant found the optimal answer: 1005304678 == 1005304678
6 Correct 1 ms 204 KB contestant found the optimal answer: 933702 == 933702
7 Correct 1 ms 204 KB contestant found the optimal answer: 25082842857 == 25082842857
8 Correct 1 ms 204 KB contestant found the optimal answer: 687136 == 687136
9 Correct 1 ms 204 KB contestant found the optimal answer: 27295930079 == 27295930079
10 Correct 1 ms 204 KB contestant found the optimal answer: 29000419931 == 29000419931
# Verdict Execution time Memory Grader output
1 Correct 1 ms 204 KB contestant found the optimal answer: 610590000 == 610590000
2 Correct 1 ms 204 KB contestant found the optimal answer: 311760000 == 311760000
3 Correct 2 ms 460 KB contestant found the optimal answer: 1989216017013 == 1989216017013
4 Correct 1 ms 204 KB contestant found the optimal answer: 1499437552673 == 1499437552673
5 Correct 2 ms 344 KB contestant found the optimal answer: 1019625819 == 1019625819
6 Correct 2 ms 332 KB contestant found the optimal answer: 107630884 == 107630884
7 Correct 2 ms 460 KB contestant found the optimal answer: 475357671774 == 475357671774
8 Correct 1 ms 332 KB contestant found the optimal answer: 193556962 == 193556962
9 Correct 1 ms 204 KB contestant found the optimal answer: 482389919803 == 482389919803
10 Correct 1 ms 332 KB contestant found the optimal answer: 490686959791 == 490686959791
# Verdict Execution time Memory Grader output
1 Correct 1 ms 332 KB contestant found the optimal answer: 21503404 == 21503404
2 Correct 1 ms 332 KB contestant found the optimal answer: 140412195 == 140412195
3 Correct 7 ms 1100 KB contestant found the optimal answer: 49729674225461 == 49729674225461
4 Correct 1 ms 292 KB contestant found the optimal answer: 37485571387523 == 37485571387523
5 Correct 8 ms 1132 KB contestant found the optimal answer: 679388326 == 679388326
6 Correct 7 ms 1100 KB contestant found the optimal answer: 4699030287 == 4699030287
7 Correct 8 ms 1132 KB contestant found the optimal answer: 12418819758185 == 12418819758185
8 Correct 6 ms 1100 KB contestant found the optimal answer: 31093317350 == 31093317350
9 Correct 3 ms 460 KB contestant found the optimal answer: 12194625429236 == 12194625429236
10 Correct 4 ms 588 KB contestant found the optimal answer: 12345131038664 == 12345131038664
# Verdict Execution time Memory Grader output
1 Correct 4 ms 844 KB contestant found the optimal answer: 1818678304 == 1818678304
2 Correct 4 ms 912 KB contestant found the optimal answer: 1326260195 == 1326260195
3 Correct 69 ms 8516 KB contestant found the optimal answer: 4973126687469639 == 4973126687469639
4 Correct 5 ms 844 KB contestant found the optimal answer: 3748491676694116 == 3748491676694116
5 Correct 53 ms 5504 KB contestant found the optimal answer: 1085432199 == 1085432199
6 Correct 56 ms 6192 KB contestant found the optimal answer: 514790755404 == 514790755404
7 Correct 62 ms 6600 KB contestant found the optimal answer: 1256105310476641 == 1256105310476641
8 Correct 46 ms 5552 KB contestant found the optimal answer: 3099592898816 == 3099592898816
9 Correct 54 ms 6212 KB contestant found the optimal answer: 1241131419367412 == 1241131419367412
10 Correct 67 ms 7812 KB contestant found the optimal answer: 1243084101967798 == 1243084101967798
# Verdict Execution time Memory Grader output
1 Correct 34 ms 5712 KB contestant found the optimal answer: 19795776960 == 19795776960
2 Correct 32 ms 5624 KB contestant found the optimal answer: 19874432173 == 19874432173
3 Correct 716 ms 82996 KB contestant found the optimal answer: 497313449256899208 == 497313449256899208
4 Correct 40 ms 6092 KB contestant found the optimal answer: 374850090734572421 == 374850090734572421
5 Correct 870 ms 82888 KB contestant found the optimal answer: 36183271951 == 36183271951
6 Correct 580 ms 59180 KB contestant found the optimal answer: 51629847150471 == 51629847150471
7 Correct 648 ms 63400 KB contestant found the optimal answer: 124074747024496432 == 124074747024496432
8 Correct 476 ms 52132 KB contestant found the optimal answer: 309959349080800 == 309959349080800
9 Correct 518 ms 59280 KB contestant found the optimal answer: 124113525649823701 == 124113525649823701
10 Correct 695 ms 75000 KB contestant found the optimal answer: 124309619349406845 == 124309619349406845