[C++] 백준 15686번. 치킨배달

#include <iostream>
#include <vector>
#include <math.h>
 
using namespace std;
 
int N, M;
int city[50][50];
int chicken_dist = 100000;
vector<pair<int, int>> houses;
vector<pair<int, int>> chickens;
vector<pair<int, int>> answer((13,13));
 
 
int find_dist() {
    int dist;
    int mini_dist;
    int total = 0;
 
    for (int i = 0; i < houses.size(); i++) {
        mini_dist = 100000;
        for (int j = 0; j < M; j++) {
            dist = abs(houses[i].first - answer[j].first) + abs(houses[i].second - answer[j].second);
            if (mini_dist > dist)
                mini_dist = dist;
        }
        total += mini_dist;
    }
    return total;
}
 
void swap(int index1, int index2) {
    pair<int, int> temp = chickens[index1];
    chickens[index1] = chickens[index2];
    chickens[index2] = temp;
}
 
void recursive(int index, int size) {
    if (size == M) {
        int temp_dist = find_dist();
        if (chicken_dist > temp_dist)
            chicken_dist = temp_dist;
        return;
    }
 
    for (int i = index; i < chickens.size(); i++) {
        if (chickens[i].first == -1)
            continue;
        answer[size] = chickens[i];
        chickens[i].first = -1;
        recursive(i, size + 1);
        chickens[i].first = answer[size].first;
    }
}
 
int main() {
    cin >> N >> M;
 
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            cin >> city[i][j];
            if (city[i][j] == 1)
                houses.push_back(make_pair(i, j));
            else if (city[i][j] == 2)
                chickens.push_back(make_pair(i, j));
        }
    }
    recursive(0, 0);
    cout << chicken_dist << endl;
 
    return 0;
}