[백준 1987: 알파벳] - C++

www.acmicpc.net/problem/1987

1987번: 알파벳

#include<iostream>
#include<string>
using namespace std;

int r, c;
char map[20][20];
bool check[26];
int result = 0;

int dir[4][2] = {
	{-1,0}
	,{0,1}
	,{1,0}
	,{0,-1}
};

void D(int _x, int _y, int cnt)
{
	if (result < cnt)
		result = cnt;
	for (int i = 0; i < 4; i++)
	{
		int nextX = _x + dir[i][0];
		int nextY = _y + dir[i][1];

		if (nextX < 0 || nextY < 0 || r <= nextX || c <= nextY)
			continue;
		int num = map[nextX][nextY] - '0';
		if (check[num] == false)
		{
			check[num] = true;
			D(nextX, nextY, cnt + 1);
			check[num] = false;
		}
	}
}

int main() {
	string n;
	cin >> r >> c;

	for (int i = 0; i < r; i++)
	{
		cin >> n;
		for (int j = 0; j < c; j++)
		{
			map[i][j] = n[j];
		}
	}


	check[map[0][0] - '0'] = true;
	D(0, 0, 1);


	cout << result << endl;
	return 0;
}