View Compilation Error

0_0_25569746_14007.cpp: In function 'int dfs(int, int, int, int)':
0_0_25569746_14007.cpp:41:8: error: 'vis' was not declared in this scope
     if(vis[len][res1][res2][res3] == T)   return dp[len][res1][res2][res3];
        ^
0_0_25569746_14007.cpp:55:5: error: 'vis' was not declared in this scope
     vis[len][res1][res2][res3] = T;
     ^