Code solution : C++
long long result=LLONG_MIN , total= accumulate(begin(A),end(A),0L), left=0;
for(int i=0;i<n;i++){
left+= A[i]; //sum till i from start
long long right= total-left+A[i]; //sum till i from end
result= max({result,left,right}); //update global max
}
return res;