View Compilation Error

0_0_31230629_15800.cpp: In function 'int main()':
0_0_31230629_15800.cpp:20:13: error: return-statement with no value, in function returning 'int' [-fpermissive]
             return ;
             ^
0_0_31230629_15800.cpp:31:27: error: 'dfs' was not declared in this scope
         if(!dfs(nums,0,sum)){
                           ^