Submission #403229

#	Time	Username	Problem	Language	Result	Execution time	Memory
403229		monus1042	Boxes with souvenirs (IOI15_boxes)	C++17	100 / 100	920 ms	365068 KiB

boxes

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

const ll inf = 8e18;
const int NAX = 10000005;
vector<ll> dp(NAX, inf);

int maxRight = 0;

ll subtwo(int N, int K, int L, int p[]){
	ll answer = 0;
	if (L==1) return answer;
    int mxd = L/2;
	int cnt = 0, cntright = 0;
	for (int i=0; i<N; i++){
		if (p[i] <= mxd) cnt++;
		if ((p[i] == 0 || p[i] >= mxd+1) && N%2==1) cntright++;
		else if ((p[i] == 0 || p[i] >= mxd) && N%2==0) cntright++;
	}
	if (cnt == N) return 2LL*p[N-1];
	if (cntright == N) return 2LL*(L-p[0]);
	answer = L;
	ll maxleft, maxright;
	maxleft = maxright = 0;
    for (int i=0; i<N; i++){
		if (p[i] <= mxd){
			maxleft = max(maxleft,(ll)p[i]);
		}else{
			maxright = max(maxright, (ll)L-p[i]);
		}
	}
	ll answer2 = maxleft*2LL + maxright*2LL;
	answer = min(answer, answer2);
	return answer;
}

ll subone(int N, int K, int L, int p[]){
	ll answer = 0;
	for (int i=0; i<N; i++){
		answer = answer + min(p[i],L-p[i])*2;
	}
	return answer;
}

ll subAllPoints(int N, const int K, int L, int p[]){
	vector<int> ar;
	for (int i=0; i<N; i++){
		ar.push_back(p[i]);
	}
	reverse(ar.begin(), ar.end());
	while(ar.size() && ar.back() == 0) ar.pop_back();
	reverse(ar.begin(), ar.end());
	if (ar.empty()) return 0;
	vector<int> le,ri;
	int mxd = L/2;
	for (int i=0; i<ar.size(); i++){
		if (ar[i] <= mxd) le.push_back(ar[i]);
		else ri.push_back(ar[i]);
	}
	//
	reverse(ri.begin(), ri.end());
	vector<ll> ldp,rdp;
	ldp.push_back(0);
	rdp.push_back(0);
	for (int i=0; i<le.size(); i++){
		ldp.push_back(-1);
		int cpos = i+1;
		int lpos = max(1,cpos-K+1);
		ldp[cpos] = ldp[lpos-1] + le[i];
	}
	for (int i=0; i<ri.size(); i++){
		rdp.push_back(-1);
		int cpos = i+1;
		int lpos = max(1,cpos-K+1);
		rdp[cpos] = rdp[lpos-1] + (L - ri[i]);
	}
	//compte dp: (go in reverse of array dp right)
	for (int i=(int)rdp.size()-1, helpermxR=0; i>=0; i--,helpermxR++){
		int sz = (int)rdp.size()-1 - i;
		ll newbest = (ll)sz / K * L + rdp[i]*2;
		dp[helpermxR%K] = min(dp[helpermxR%K], newbest);
		maxRight = max(maxRight,helpermxR%K);
	}
	// compute the final answer:
	ll answer = inf;
	for (int i=0; i<ldp.size(); i++){
		ll curans = ldp[i] * 2;
		int sz = (int)ldp.size()-1 - i;
		ll remaleft = (ll)((ll)sz + K-1) / K * L;
		curans = curans + remaleft;
		int complement = 0;
		if (sz%K) complement = K - sz%K;
		complement = min(complement, maxRight);
		ll curansRight = dp[complement];
		curans = curans + curansRight;
		answer = min(answer, curans);
	}
	return answer;
}

ll delivery(int N, int K, int L, int p[]) {
	if (K==1) return subone(N,K,L,p);
	else if (K==N) return subtwo(N,K,L,p);
	else return subAllPoints(N,K,L,p);
}

Compilation message (stderr)

boxes.cpp: In function 'll subtwo(int, int, int, int*)':
boxes.cpp:12:22: warning: unused parameter 'K' [-Wunused-parameter]
   12 | ll subtwo(int N, int K, int L, int p[]){
      |                  ~~~~^
boxes.cpp: In function 'll subone(int, int, int, int*)':
boxes.cpp:39:22: warning: unused parameter 'K' [-Wunused-parameter]
   39 | ll subone(int N, int K, int L, int p[]){
      |                  ~~~~^
boxes.cpp: In function 'll subAllPoints(int, int, int, int*)':
boxes.cpp:58:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |  for (int i=0; i<ar.size(); i++){
      |                ~^~~~~~~~~~
boxes.cpp:67:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |  for (int i=0; i<le.size(); i++){
      |                ~^~~~~~~~~~
boxes.cpp:73:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   73 |  for (int i=0; i<ri.size(); i++){
      |                ~^~~~~~~~~~
boxes.cpp:88:17: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   88 |  for (int i=0; i<ldp.size(); i++){
      |                ~^~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 10 / 10
• Subtask 3: 15 / 15
• Subtask 4: 15 / 15
• Subtask 5: 20 / 20
• Subtask 6: 30 / 30