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.io.*;
  import java.util.*;
  import java.lang.*;
  
  public class A_Computer_Game {
  
      static final int MOD = (int) 1e9 + 7;
      static final int INT_POSITIVE_INFINITY = Integer.MAX_VALUE;
      static final long LONG_POSITIVE_INFINITY = Long.MAX_VALUE;
      static final int INT_NEGATIVE_INFINITY = Integer.MIN_VALUE;
      static final long LONG_NEGATIVE_INFINITY = Long.MIN_VALUE;
      static StringBuilder result = new StringBuilder();
      static Pair[][] visited = new Pair[3][101];
  
      static class Pair {
          int a;
          boolean b;
  
          public Pair(int a, boolean b) {
              this.a = a;
              this.b = b;
          }
      }
  
      public static void main(String args[]) throws IOException {
          FastReader fr = new FastReader();
  
          int tc = fr.nextInt();
          while (tc-- > 0) {
              int n = fr.nextInt();
              int[][] grid = new int[2][n];
  
              for (int i = 0; i < 2; i++) {
                  for (int j = 0; j < n; j++) {
                      visited[i][j] = new Pair(-1, false);
                  }
              }
  
              for (int i = 0; i < 2; i++) {
                  char[] arr = fr.nextLine().toCharArray();
                  for (int j = 0; j < n; j++) {
                      grid[i][j] = Integer.parseInt(arr[j] + "");
                  }
              }
              result.append(dfs(grid, 0, 0, n) ? "YES\n" : "NO\n");
          }
          System.out.print(result);
      }
  
      static boolean dfs(int[][] grid, int i, int j, int n) {
          if (i < 0 || j < 0 || i >= 2 || j >= n || grid[i][j] == 1)
              return false;
          if (visited[i][j].a != -1)
              return visited[i][j].b;
          if (i == 1 && j == n - 1 && grid[i][j] == 0)
              return true;
          visited[i][j].a = 1;
          visited[i][j].b = dfs(grid, i + 1, j + 1, n) || dfs(grid, i + 1, j, n) || dfs(grid, i, j + 1, n)
                  || dfs(grid, i - 1, j + 1, n);
          return visited[i][j].b;
      }
  
      static class FastReader {
          InputStreamReader ir;
          BufferedReader br;
          StringTokenizer st;
  
          public FastReader() {
              ir = new InputStreamReader(System.in);
              br = new BufferedReader(ir);
          }
  
          String next() {
              while (st == null || !st.hasMoreElements()) {
                  try {
                      st = new StringTokenizer(br.readLine());
                  } catch (IOException e) {
                      e.printStackTrace();
                  }
              }
              return st.nextToken();
          }
  
          int nextInt() {
              return Integer.parseInt(next());
          }
  
          long nextLong() {
              return Long.parseLong(next());
          }
  
          double nextDouble() {
              return Double.parseDouble(next());
          }
  
          String nextLine() {
              String str = "";
              try {
                  str = br.readLine();
              } catch (IOException e) {
                  e.printStackTrace();
              }
              return str;
          }
      }
  
      static int fastPow(long b, long e) {
          long curr = b;
          long res = 1;
  
          while (e != 0) {
              if ((e & 1) != 0) {
                  res = (res * curr) % MOD;
              }
              curr = (curr * curr) % MOD;
              e >>= 1;
          }
  
          return (int) res;
      }
  
      static int gcd(int a, int b) {
          if (b > a) {
              return gcd(b, a);
          }
  
          if (b == 0) {
              return a;
          }
  
          return gcd(b, a % b);
      }
  
  }