Submission #197945

#	Time	Username	Problem	Language	Result	Execution time	Memory
197945		songc	Split the sequence (APIO14_sequence)	C++14	49 / 100	344 ms	131076 KiB

sequence

#include <bits/stdc++.h>
using namespace std;
typedef long long LL;
typedef pair<LL,LL> pii;

int N, K;
LL S[101010];
int P[101010][220];

struct Line{
	LL m, k;
	int id;
};

bool popchk(Line a, Line b, Line c){
	return ((__int128)b.k-c.k)*(b.m-a.m) <= ((__int128)a.k-b.k)*(c.m-b.m);
}

struct ConvHull{
	vector<Line> V;
	int p;

	void push(Line l){
		if (!V.empty() && V.back().m == l.m) return;
		while (V.size()>2 && popchk(V[V.size()-2], V.back(), l)){
			V.pop_back();
			if (V.size() <= p) p--;
		}
		V.push_back(l);
	}

	pii read(LL x){
		while (p < V.size()-1 && V[p].m*x+V[p].k <= V[p+1].m*x+V[p+1].k) p++;
		return pii(V[p].m*x+V[p].k, V[p].id);
	}

} CHT[220];

int main(){
	scanf("%d %d", &N, &K);
	K++;
	for (int i=1; i<=N; i++){
		scanf("%lld", &S[i]);
		S[i] += S[i-1];
	}
	CHT[0].push((Line){0, 0, 0});
	for (int i=1; i<=N; i++){
		for (int j=1; j<=min(i, K); j++){
			LL ret;
			tie(ret, P[i][j]) = CHT[j-1].read(S[i]);
			if (i == N && j == K) printf("%lld\n", ret);
			CHT[j].push((Line){S[i], ret-S[i]*S[i], i});
		}
	}
	for (int i=K-1, p=P[N][K]; i; p=P[p][i], i--) printf("%d ", p); 
	printf("\n");
	return 0;
}

Compilation message (stderr)

sequence.cpp: In member function 'void ConvHull::push(Line)':
sequence.cpp:27:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    if (V.size() <= p) p--;
        ~~~~~~~~~^~~~
sequence.cpp: In member function 'pii ConvHull::read(LL)':
sequence.cpp:33:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while (p < V.size()-1 && V[p].m*x+V[p].k <= V[p+1].m*x+V[p+1].k) p++;
          ~~^~~~~~~~~~~~
sequence.cpp: In function 'int main()':
sequence.cpp:40:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d", &N, &K);
  ~~~~~^~~~~~~~~~~~~~~~~
sequence.cpp:43:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%lld", &S[i]);
   ~~~~~^~~~~~~~~~~~~~~

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