View Compilation Error

0_0_39700704_6999.cpp:4:21: error: 'j' was not declared in this scope
    4 | int a[15][15],b[15][j];
      |                     ^
0_0_39700704_6999.cpp: In function 'void dfs(int)':
0_0_39700704_6999.cpp:17:13: error: 'b' was not declared in this scope
   17 |         if(!b[i][j]){
      |             ^