1391 检查是否存在有效路径 DFS

class Solution {
public:
    bool res=false;
    bool hasValidPath(vector<vector<int>>& grid) {
        vector<vector<bool>> visit(grid.size(),vector<bool>(grid[0].size(),false));
        DFS(grid,visit,0,0);
        return res;
    }
    void DFS(vector<vector<int>>& grid,vector<vector<bool>>& visit,int i,int j)
    {
        visit[i][j]=true;
        if(i==grid.size()-1 && j==grid[0].size()-1)
        {
            res=true;
            return;
        }
        if(grid[i][j]==1)
        {
            if(j+1<grid[0].size() && !visit[i][j+1] && (grid[i][j+1]==1 ||grid[i][j+1]==3 || grid[i][j+1]==5))
            {
                DFS(grid,visit,i,j+1);
            }
            if(j-1>=0 && !visit[i][j-1] && (grid[i][j-1]==1 || grid[i][j-1]==4 || grid[i][j-1]==6))
            {
                DFS(grid,visit,i,j-1);
            }
        }
        if(grid[i][j]==2)
        {
            if(i+1<grid.size() && !visit[i+1][j] && (grid[i+1][j]==2 || grid[i+1][j]==5 || grid[i+1][j]==6))
            {
                DFS(grid,visit,i+1,j);
            }
            if(i-1>=0 && !visit[i-1][j] && (grid[i-1][j]==2 ||grid[i-1][j]==3 || grid[i-1][j]==4))
            {
                DFS(grid,visit,i-1,j);
            }
        }
        if(grid[i][j]==3)
        {
            if(i+1<grid.size() && !visit[i+1][j] && (grid[i+1][j]==2 ||grid[i+1][j]==5 || grid[i+1][j]==6))
            {
                DFS(grid,visit,i+1,j);
            }
            if(j-1>=0 && !visit[i][j-1] && (grid[i][j-1]==1 || grid[i][j-1]==4 || grid[i][j-1]==6 ))
            {
                DFS(grid,visit,i,j-1);
            }
        }
        if(grid[i][j]==4)
        {
            if(i+1<grid.size() && !visit[i+1][j] && (grid[i+1][j]==2 ||grid[i+1][j]==5 || grid[i+1][j]==6))
            {
                DFS(grid,visit,i+1,j);
            }
            if(j+1<=grid[0].size() && !visit[i][j+1] && (grid[i][j+1]==1 || grid[i][j+1]==3 || grid[i][j+1]==5))
            {
                DFS(grid,visit,i,j+1);
            }
        }
        if(grid[i][j]==5)
        {
            if(i-1>=0 && !visit[i-1][j] && (grid[i-1][j]==2 ||grid[i-1][j]==3 || grid[i-1][j]==4))
            {
                DFS(grid,visit,i-1,j);
            }
            if(j-1>=0 && !visit[i][j-1] && (grid[i][j-1]==1 || grid[i][j-1]==4 || grid[i][j-1]==6 ))
            {
                DFS(grid,visit,i,j-1);
            }
            
        }
        if(grid[i][j]==6)
        {
            if(i-1>=0 && !visit[i-1][j] && (grid[i-1][j]==2 ||grid[i-1][j]==3 || grid[i-1][j]==4))
            {
                DFS(grid,visit,i-1,j);
            }
            if(j+1<=grid[0].size() && !visit[i][j+1] && (grid[i][j+1]==1 || grid[i][j+1]==3 || grid[i][j+1]==5))
            {
                DFS(grid,visit,i,j+1);
            }
        }
        visit[i][j]=false;
        return;
    }
};