View Compilation Error

0_0_18345046_721.cpp: In function 'int main()':
0_0_18345046_721.cpp:27:24: error: 'a' was not declared in this scope
             dp[tmp]=dp[a[i]-1]+1;
                        ^
0_0_18345046_721.cpp:34:13: error: 'mx' was not declared in this scope
             mx=max(w,mx);
             ^
0_0_18345046_721.cpp:36:23: error: 'mx' was not declared in this scope
         printf("%d\n",mx);
                       ^