View Compilation Error

0_0_21000107_26824.cpp: In function 'void dfs(int, int, int)':
0_0_21000107_26824.cpp:103:12: error: expected primary-expression before '?' token
       ans <?= now;
            ^
0_0_21000107_26824.cpp:103:13: error: expected primary-expression before '=' token
       ans <?= now;
             ^
0_0_21000107_26824.cpp:103:18: error: expected ':' before ';' token
       ans <?= now;
                  ^
0_0_21000107_26824.cpp:103:18: error: expected primary-expression before ';' token