View Compilation Error

0_0_36575877_4640.cpp: In function 'void solve()':
0_0_36575877_4640.cpp:21:14: error: expected unqualified-id before '[' token
         auto [val, idx] = a[i];
              ^
0_0_36575877_4640.cpp:22:20: error: 'val' was not declared in this scope
         int best = val + b[0];
                    ^
0_0_36575877_4640.cpp:35:13: error: 'idx' was not declared in this scope
         ans[idx][0] = rank;
             ^
0_0_36575877_4640.cpp:39:14: error: expected unqualified-id before '[' token
         auto [val, idx] = a[i];
              ^
0_0_36575877_4640.cpp:40:21: error: 'val' was not declared in this scope
         int worst = val + b[n - 1];
                     ^
0_0_36575877_4640.cpp:60:13: error: 'idx' was not declared in this scope
         ans[idx][1] = rank;
             ^