View Compilation Error

0_0_33481739_14427.cpp: In function 'void bfs(int)':
0_0_33481739_14427.cpp:39:17: error: 'f' was not declared in this scope
                 f[v][0] = t;
                 ^
0_0_33481739_14427.cpp: In function 'int lca(int, int)':
0_0_33481739_14427.cpp:50:19: error: 'f' was not declared in this scope
         if (depth[f[y][i]] >= depth[x]) y = f[y][i];
                   ^
0_0_33481739_14427.cpp:53:13: error: 'f' was not declared in this scope
         if (f[x][i] != f[y][i]) x = f[x][i], y = f[y][i];
             ^
0_0_33481739_14427.cpp:54:12: error: 'f' was not declared in this scope
     return f[x][0];
            ^