아기상어 심심풀이

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

int arr[20][20];
bool visit[20][20];
int N;

struct Node {
	int y;
	int x;
	int dis;
};


bool compare(Node a1, Node a2)
{
	if (a1.dis != a2.dis)
	{
		return a1.dis < a2.dis;
	}
	else
	{
		if (a1.y != a2.y)
		{
			return a1.y < a2.y;
		}
		else
		{
			return a1.x < a2.x;
		}
	}
}

int dx[4] = { 0,0,-1,1 };
int dy[4] = { -1,1,0,0 };
int age, ate;

int main(void)
{

	cin >> N;
	queue<Node> shark;
	for (int i = 0; i < N; i++)
	{
		for (int j = 0; j < N; j++)
		{
			cin >> arr[i][j];
			if (arr[i][j] == 9)
			{
				shark.push({ i,j,0 });
				arr[i][j] = 0;
			}
		}
	}
	age = 2;
	ate = 0;
	int count = 0;

	while (1)
	{
		vector<Node> fish;
		
		memset(visit, 0, sizeof(visit));
		
		while (!shark.empty())
		{
			int y = shark.front().y;
			int x = shark.front().x;
			int dis = shark.front().dis;
			shark.pop();

			for (int i = 0; i < 4; i++)
			{
				int newy = y + dy[i];
				int newx = x + dx[i];

				if (newy < N && newy >= 0 && newx < N && newx >= 0)
				{
					if (arr[newy][newx] <= age && !visit[newy][newx])
					{
						visit[newy][newx] = true;
						if (arr[newy][newx] < age && arr[newy][newx])
						{
							fish.push_back({ newy,newx,dis + 1 });
						}
						shark.push({ newy,newx,dis + 1 });
					}
				}
			}
		}
		if (fish.empty())
		{
			break;
		}

		sort(fish.begin(), fish.end(),compare);
		shark.push({ fish[0].y, fish[0].x, 0 });
		arr[fish[0].y][fish[0].x] = 0;
		ate++;
		count += fish[0].dis;
		if (ate == age)
		{
			ate = 0;
			age++;
		}
	}

	cout << count << endl;
    
}