• Source 
    1. import java.io.*;
    2. class ISSNAKE
    3. {
    4.     static BufferedReader xy=new BufferedReader(new InputStreamReader(System.in));
    5.     static int r=0;
    6.     static int n=0;
    7.     static char ar[][];
    8.     static int x=0;static int y=0;
    9.     static int p=-1;static int q=-1;
    10.     public static void main(String args[])throws IOException
    11.     {
    12.         r=Integer.parseInt(xy.readLine());
    13.         for(int i=0;i<r;i++)
    14.         {
    15.             daff();
    16.         }
    17.     }
    18.  
    19.     public static void input()throws IOException
    20.     {
    21.         n=Integer.parseInt(xy.readLine());
    22.         ar=new char[2][n];
    23.         String s=xy.readLine();
    24.         for(int i=0;i<n;i++)
    25.             ar[0][i]=s.charAt(i);
    26.         s=xy.readLine();
    27.         for(int i=0;i<n;i++)
    28.             ar[1][i]=s.charAt(i);
    29.     }
    30.  
    31.     static void find()
    32.     {
    33.         for(int i=0;i<2;i++)
    34.         {
    35.             for(int j=0;j<n;j++)
    36.             {
    37.                 if (ar[i][j]=='#')
    38.                 {
    39.                     x=i;
    40.                     y=j;
    41.                     if(i==0&&ar[1][j]=='#')
    42.                     {   
    43.                         p=1;
    44.                         q=j;
    45.                     }
    46.                     return;
    47.                 }
    48.             }
    49.         }
    50.     }
    51.  
    52.     static void kill(char arr[][],int a,int b)
    53.     {
    54.         arr[a][b]='.';
    55.         try
    56.         {
    57.             if(a==0&& arr[a+1][b]=='#')
    58.                 kill (arr,a+1,b);
    59.             else if(a==1&& arr[a-1][b]=='#')
    60.                 kill (arr,a-1,b);
    61.             else if (arr[a][b+1]=='#')
    62.                 kill (arr,a,b+1);
    63.         }
    64.         catch(Exception e)
    65.         {
    66.         }
    67.     }    
    68.  
    69.     static boolean check(char arr[][])
    70.     {
    71.         for(int i=0;i<2;i++)
    72.         {
    73.             for(int j=0;j<n;j++)
    74.             {
    75.                 if (arr[i][j]=='#')
    76.                 {
    77.                     return false;
    78.                 }
    79.             }
    80.         }
    81.         return true;
    82.     }
    83.  
    84.     public static void daff()throws IOException
    85.     {
    86.  
    87.         input();
    88.         find();
    89.  
    90.         if(p==-1)
    91.         {
    92.             kill(ar,x,y);
    93.             if(check(ar))
    94.                 System.out.println("yes");
    95.             else
    96.                 System.out.println("no");
    97.         }
    98.  
    99.         if(p!=-1)
    100.         {
    101.             char newar[][]=new char[2][n];
    102.             for(int i=0;i<2;i++)
    103.             {
    104.                 for(int j=0;j<n;j++)
    105.                 {
    106.                     newar[i][j]=ar[i][j];
    107.                 }
    108.             }
    109.  
    110.             kill(ar,x,y);
    111.             boolean flag=check(ar);
    112.             if(flag==true)
    113.             {
    114.                 System.out.println("yes");
    115.                 return;
    116.             }
    117.             else
    118.             {
    119.                 kill(newar,p,q);
    120.                 if(check(newar))
    121.                     System.out.println("yes");
    122.                 else
    123.                     System.out.println("no");
    124.             }
    125.         }
    126.  
    127.     }
    128. }
    129.