Submission #1023539

#	Time	Username	Problem	Language	Result	Execution time	Memory
1023539		daffuwu	Split the sequence (APIO14_sequence)	C++14	62 / 100	531 ms	84428 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
#define fr first
#define sc second
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
 
int n, k, opt[100002][202], ps[100069];
long long dp[100069][2];
 
struct line
{
    int m;
    long long c;
    int id;
    long long f(int x)
    {
        return 1ll*m*x+c;
    }
    double intersect(line oth)
    {
        return 1.0*(c-oth.c)/(oth.m-m);
    }
} cur;
vector<line> vc;
 
int main() 
{
    int i, j, ii, c;
    scanf("%d%d", &n, &k);
    k++;
    for (i=1; i<=n; i++)
    {
        scanf("%d", ps+i);
        ps[i] += ps[i-1];
    }
    for (c=2; c<=k; c++)
    {
        for (i=c, j=0; i<=n; i++)
        {
            vc.push_back({ps[i-1], dp[i-1][(c+1)%2]-1ll*ps[i-1]*ps[i-1], i-1});
            for (; j+1<vc.size() && vc[j].f(ps[i])<=vc[j+1].f(ps[i]); j++);
            j = min(j, (int)vc.size()-1);
            dp[i][c%2] = vc[j].f(ps[i]);
            opt[i][c] = vc[j].id;
            cur = {ps[i], dp[i][(c+1)%2]-1ll*ps[i]*ps[i], i};
            for (; vc.size()>=2 && vc[vc.size()-2].intersect(vc.back())>=vc.back().intersect(cur); vc.pop_back());
        }
        vc.clear();
    }
    printf("%lld\n", dp[n][k%2]);
    for (i=n, c=k; c>=2; i=opt[i][c], c--)
    {
        printf("%d ", opt[i][c]);
    }
    printf("\n");
}

Compilation message (stderr)

sequence.cpp: In function 'int main()':
sequence.cpp:41:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<line>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |             for (; j+1<vc.size() && vc[j].f(ps[i])<=vc[j+1].f(ps[i]); j++);
      |                    ~~~^~~~~~~~~~
sequence.cpp:28:15: warning: unused variable 'ii' [-Wunused-variable]
   28 |     int i, j, ii, c;
      |               ^~
sequence.cpp:29:10: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   29 |     scanf("%d%d", &n, &k);
      |     ~~~~~^~~~~~~~~~~~~~~~
sequence.cpp:33:14: warning: ignoring return value of 'int scanf(const char*, ...)' declared with attribute 'warn_unused_result' [-Wunused-result]
   33 |         scanf("%d", ps+i);
      |         ~~~~~^~~~~~~~~~~~

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