description: Monocarp is playing a computer game. Now he wants to complete the first level of this game.
  
  A level is a rectangular grid of 2 rows and n columns. Monocarp controls a character, which starts in cell (1, 1) — at the intersection of the 1-st row and the 1-st column.
  
  Monocarp's character can move from one cell to another in one step if the cells are adjacent by side and/or corner. Formally, it is possible to move from cell (x_1, y_1) to cell (x_2, y_2) in one step if |x_1 - x_2| ≤ 1 and |y_1 - y_2| ≤ 1. Obviously, it is prohibited to go outside the grid.
  
  There are traps in some cells. If Monocarp's character finds himself in such a cell, he dies, and the game ends.
  
  To complete a level, Monocarp's character should reach cell (2, n) — at the intersection of row 2 and column n.
  
  Help Monocarp determine if it is possible to complete the level.
  
  Input
  
  The first line contains a single integer t (1 ≤ t ≤ 100) — the number of test cases. Then the test cases follow. Each test case consists of three lines.
  
  The first line contains a single integer n (3 ≤ n ≤ 100) — the number of columns.
  
  The next two lines describe the level. The i-th of these lines describes the i-th line of the level — the line consists of the characters '0' and '1'. The character '0' corresponds to a safe cell, the character '1' corresponds to a trap cell.
  
  Additional constraint on the input: cells (1, 1) and (2, n) are safe.
  
  Output
  
  For each test case, output YES if it is possible to complete the level, and NO otherwise.
  
  Example
  
  Input
  
  
  4
  3
  000
  000
  4
  0011
  1100
  4
  0111
  1110
  6
  010101
  101010
  
  
  Output
  
  
  YES
  YES
  NO
  YES
  
  Note
  
  Consider the example from the statement.
  
  In the first test case, one of the possible paths is (1, 1) → (2, 2) → (2, 3).
  
  In the second test case, one of the possible paths is (1, 1) → (1, 2) → (2, 3) → (2, 4).
  
  In the fourth test case, one of the possible paths is (1, 1) → (2, 2) → (1, 3) → (2, 4) → (1, 5) → (2, 6).
solution: 
  import java.util.*;
  public class Sant {
  
  	public static void main(String[] args) {
  		// TODO Auto-generated method stub
         Scanner sc=new Scanner(System.in);
         int t=sc.nextInt();
         while(t--!=0) {
      	   int n=sc.nextInt();
      	   int a[][]=new int[2][n];
      	   String first=sc.next();
      	   String second =sc.next();
      	   for(int i=0;i<2;i++) {
      		   for(int j=0;j<n;j++) {
      			   if(i==0)a[i][j]=first.charAt(j)-'0';
      			   else a[i][j]=second.charAt(j)-'0';
      		   }
      		   
      	   }
      	   int i=0,j=0;
      	   boolean vis[][]=new boolean[2][n];
      	   boolean pos=true;
      	  while(j<n-1) {
  //    		  System.out.println("in here and i="+i+" and j="+j);
      		  if(a[i][j]==0) {
      			  vis[i][j]=true;
      			  if(j+1<n && !vis[i][j+1] && a[i][j+1]==0) {
      				  j+=1;
      			  }
      			  else if(i+1<2 &&!vis[i+1][j] && a[i+1][j]==0) {
      				  i+=1;
      			  }
      			  else if(i+1<2 && j+1<n && !vis[i+1][j+1] && a[i+1][j+1]==0) {
      				  i+=1;
      				  j+=1;
      			  }
      			  else if(i-1>=0 &&!vis[i-1][j] && a[i-1][j]==0) {
      				  i-=1;
      			  }
      			  else if(i-1>=0 && j+1<n &&!vis[i-1][j+1] && a[i-1][j+1]==0) {
      				  i-=1;
      				  j+=1;
      			  }
      			  else {
      				  pos=false;
      				  break;
      			  }
      			  
      		  }
      		  else {
      			  pos=false;
      			  break;
      		  }
      	  }
      	  if(pos)System.out.println("YES");
      	  else System.out.println("NO");
         }
  	   
     
    
  	}
  
  }
  