Submission #128012

#	Time	Username	Problem	Language	Result	Execution time	Memory
128012		Sorting	Boxes with souvenirs (IOI15_boxes)	C++14	100 / 100	1084 ms	254280 KiB

boxes

#include <bits/stdc++.h>

using namespace std;

const int N = 1e7 + 7;
const long long inf = 1e18 + 7;

vector<long long> v1, v2, v3, v4, pr1, pr2;

void output(vector<long long> v){
	for(long long &x: v){
		cout << x << " ";
	}
	cout << endl;
}

long long delivery(int n, int k, int l, int *positions){
	sort(positions, positions + n);
	
	int idx = 0;

	for(; idx < n && positions[idx] <= l / 2; idx++){
		v1.push_back(positions[idx]);
	}
	for(; idx < n; idx++){
		v2.push_back(l - positions[idx]);
	}
	if(!v2.empty()){
		reverse(v2.begin(), v2.end());
	}

	for(int i = 0 ; i < (int)v1.size(); i++){
		if(i >= k){
			pr1.push_back(pr1[i - k] + v1[i] * 2ll);
		}
		else{
			pr1.push_back(v1[i] * 2ll);
		}
	}

	for(int i = 0 ; i < (int)v2.size(); i++){
		if(i >= k){
			pr2.push_back(pr2[i - k] + v2[i] * 2ll);
		}
		else{
			pr2.push_back(v2[i] * 2ll);
		}
	}

	long long ans = 0, sum1 = 0, sum2 = 0;

	for(int i = -1; true;){
		if(i + k >= (int)v1.size()){
			for(++i; i < (int)v1.size(); ++i){
				v3.push_back(v1[i]);
			}
			break;
		}
		i += k;
		sum1 += (long long)v1[i] * 2ll;
	}
	for(int i = -1; true;){
		if(i + k >= (int)v2.size()){
			for(++i; i < (int)v2.size(); ++i){
				v4.push_back(v2[i]);
			}
			break;
		}
		i += k;
		sum2 += (long long)v2[i] * 2ll;
	}


	ans = sum1 + sum2;

	if(v3.empty() || v4.empty()){
		ans = 0;

		if(!v1.empty()){
			ans += pr1.back();
		}
		if(!v2.empty()){
			ans += pr2.back();
		}

		return ans;
	}

	ans = pr1.back() + pr2.back();

	for(int i = v1.size() - 2; i >= -1 && i >= (int)v1.size() - k; i--){
		int j = v2.size() + v1.size() - k - i - 2;

		//cout << i << " " << j << endl;

		long long curr = l;

		if(j > -1){
			curr += pr2[j];
		}
		if(i > -1){
			curr += pr1[i];
		}

		//cout << curr << endl;

		ans = min(ans, curr);
	}

	return ans;
}

/*int positions[N], n, k, l;

int main(){
	cin >> n >> k >> l;
	for(int i = 0; i < n; i++){
		cin >> positions[i];
	}

	cout << delivery(n, k, l, positions) << "\n";

	return 0;
}*/
/*
3 2 8
1 2 5
*/
/*
4 3 20
1 2 3 4
*/

Compilation message (stderr)

boxes.cpp: In function 'long long int delivery(int, int, int, int*)':
boxes.cpp:91:24: warning: conversion to 'int' from 'std::vector<long long int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
  for(int i = v1.size() - 2; i >= -1 && i >= (int)v1.size() - k; i--){
              ~~~~~~~~~~^~~
boxes.cpp:92:41: warning: conversion to 'int' from 'std::vector<long long int>::size_type {aka long unsigned int}' may alter its value [-Wconversion]
   int j = v2.size() + v1.size() - k - i - 2;
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~

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