백준 15686번 _ 치킨 배달

https://www.acmicpc.net/problem/15686

15686번: 치킨 배달

 

1. 풀이방법

 

1) 치킨집에 대한 point값, 집에 대한 point값을 저장해놓는다.

2) 치킨집을 하나 고르고, 그 치킨집과 집들의 치킨거리를 구한다.

3) 2)를 치킨집이 m개될때까지, 모든 치킨집의 1 ~ m개까지의 조합이 나올때까지 반복

 

 

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2. 코드

 

#include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <limits.h>
using namespace std;

vector<pair<int, int >>housePoint;
vector<pair<int, int>>chickenPoint;
int n, m, answer = INT_MAX;

int getDistance(pair<int, int>a, pair<int, int >b)
{
	return abs(b.first - a.first) + abs(b.second - a.second);
}

int getChickenRoad(const vector<int>& selectChickenShop)
{
	int SumOfchickenRoad = 0;
	if (selectChickenShop.size() == 0)
		return INT_MAX;
	for (int i = 0; i < (int)housePoint.size(); i++)
	{
		int chickenRoad = INT_MAX;
		for (int j = 0; j < (int)selectChickenShop.size(); j++)
		{
			chickenRoad = min(chickenRoad, getDistance(housePoint[i], chickenPoint[selectChickenShop[j]]));
		}
		SumOfchickenRoad += chickenRoad;
	}
	return SumOfchickenRoad;
}

void dfs(int idx, vector<int> selectChickenShop)
{
	if (selectChickenShop.size() > m)
		return;

	answer = min(answer, getChickenRoad(selectChickenShop));

	for (int i = idx; i < (int)chickenPoint.size(); i++)
	{
		selectChickenShop.push_back(i);
		dfs(i + 1, selectChickenShop);
		selectChickenShop.erase(--end(selectChickenShop));
	}
}

int main()
{
	cin >> n >> m;

	//입력
	int value;
	for (int i = 1; i <= n; i++)
	{
		for (int j = 1; j <= n; j++)
		{
			cin >> value;
			if (value == 1)
				housePoint.push_back({ i, j });
			else if (value == 2)
				chickenPoint.push_back({ i, j });
		}
	}

	dfs(0, vector<int>(0));
	
	cout << answer << endl;
	return 0;
}

 

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3. 후기

 

어떻게 풀지 찾기가 조금 어려웠다.