【cf 908B】B. New Year and Buggy Bot

1.题目链接。有人刚入门的学弟问我这个题该咋写，说实话题目长的我都不想看，就看了最后一句话大概猜了题意。

2.s长度只有100，答案其实不会超过24.因为4!=24,所以枚举一下阶乘就完事了吧。复杂度O(4!*len(s)).

#include<bits/stdc++.h>
using namespace std;
char mp[60][60];
int pos[4] = { 0,1,2,3 };
char s[200];
int main()
{
	int n, m;
	int sx = 0, sy = 0;
	scanf("%d%d", &n, &m);
	for (int i = 0; i < n; i++)
		for (int j = 0; j < m; j++)
		{
			scanf(" %c", &mp[i][j]);
			if (mp[i][j] == 'S')sx = i, sy = j;
		}

	scanf("%s", &s);
	int ans = 0;
	do
	{
		int curx = sx, cury = sy;
		for (int i = 0; i < strlen(s); i++)
		{
			int tem = s[i] - '0';
			if (tem == pos[0])cury--;
			else if (tem == pos[1])cury++;
			else if (tem == pos[2])curx--;
			else if (tem == pos[3])curx++;
			if (cury < 0 || cury >= m || curx < 0 || curx >= n)break;
			if (mp[curx][cury] == '#')break;
			if (mp[curx][cury] == 'E')
			{
				ans++; 
				break;
			}
		}
	} while (next_permutation(pos, pos + 4));
	printf("%d\n", ans);
}