Run id: 129808

Main.cc: In function 'int main()':
Main.cc:13:19: error: expected ')' before ';' token
     cout <<(a-1)*2;
                   ^
Main.cc:7:15: warning: unused variable 'a' [-Wunused-variable]
     long long a[51] = {0, 1, 2, 4}; // 初始化前4项（索引0~3）
               ^
Main.cc:9:15: warning: unused variable 'q' [-Wunused-variable]
     long long q = 0;
               ^
Main.cc: At global scope:
Main.cc:17:5: error: expected unqualified-id before 'return'
     return 0;
     ^