제출 #135274

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
135274		Lawliet	Split the sequence (APIO14_sequence)	C++14	33 / 100	2075 ms	87664 KiB

sequence

#include <bits/stdc++.h>
 
#define MAXK 210
#define MAXN 100010
#define INF 1000000000000000000LL
 
using namespace std;
typedef long long int lli;
typedef pair<int,int> pii; 

class ConvexHullTrick
{
	public:

		bool canRemove(lli a, lli b, lli c, lli d)
		{
			double aa = (double) a;
			double cc = (double) c;

			return aa/b <= cc/d;
		}

		void add(lli a, lli b, int i)
		{
			//printf("ADD %lld %lld\n",a,b);
			while(size > 1 && canRemove(B[size] - b , a - A[size] , B[size] - B[size - 1] , A[size - 1] - A[size]))
			{
				A.pop_back();
				B.pop_back();
				ind.pop_back();

				size--;
				//printf("POP\n");
			}

			A.push_back( a );
			B.push_back( b );
			ind.push_back( i );

			size++;
		}

		lli equation(int i, lli x) { return A[i]*x + B[i]; }

		lli query(lli x)
		{
			if(optLine >= size) optLine = size - 1;

			while(optLine < size - 1 && equation(optLine , x) <= equation(optLine + 1 , x))
				optLine++;

			//printf("---- opt = %d\n",optLine);

			return ind[ optLine ];
		}

		void clear()
		{
			A.clear(); B.clear();
			ind.clear();

			size = optLine = 0;
		}

		ConvexHullTrick() : size(0), optLine(0) {}

	private:

		int size;
		int optLine;

		vector<lli> A;
		vector<lli> B;

		vector<int> ind;
};

int n, k;
 
int v[MAXN];
int opt[MAXN][MAXK];
 
lli sv[MAXN];
lli dp[MAXN][2];

ConvexHullTrick CHT;

int main()
{
	scanf("%d %d",&n,&k);
 
	for(int g = 1 ; g <= n ; g++)
	{
		scanf("%d",&v[g]);
 
		sv[g] = sv[g - 1] + v[g];
	}
 
	dp[0][0] = dp[0][1] = -INF;
 
	for(int j = 1 ; j <= k ; j++)
	{
		CHT.add(0 , -INF , 0);

		for(int i = 1 ; i <= n ; i++)
		{
			opt[i][j] = CHT.query( sv[i] );

			int l = opt[i][j];

			dp[i][j%2] = dp[ l ][1 - j%2] - sv[l]*sv[l] + sv[l]*sv[i];

			//printf("dp(%d,%d) = %lld         %lld\n",i,j,dp[i][j%2],dp[i][1 - j%2] - sv[i]*sv[i]);
			//printf("\n");

			CHT.add(sv[i] , dp[i][1 - j%2] - sv[i]*sv[i] , i);
		}

		CHT.clear();
	}

	printf("%lld\n",dp[n][k%2]);
 
	int cur = n;

	for(int g = k ; g > 0 ; g--)
	{
		printf("%d ",opt[cur][g]);
 
		cur = opt[cur][g];
	} 
}

//dp(i,k) = dp(j - 1 , k) + sv[j - 1]*(sv[i] - sv[j - 1]) = dp(j - 1 , k) - sv[j - 1]*sv[j - 1] + sv[j - 1]*sv[i]

컴파일 시 표준 에러 (stderr) 메시지

sequence.cpp: In function 'int main()':
sequence.cpp:90:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n,&k);
  ~~~~~^~~~~~~~~~~~~~~
sequence.cpp:94:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d",&v[g]);
   ~~~~~^~~~~~~~~~~~

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