View Compilation Error

0_0_39560248_9789.cpp: In function 'void solve()':
0_0_39560248_9789.cpp:72:5: error: 'sort' was not declared in this scope; did you mean 'short'?
   72 |     sort(b.begin(), b.end());
      |     ^~~~
      |     short
0_0_39560248_9789.cpp:73:13: error: 'unique' was not declared in this scope
   73 |     b.erase(unique(b.begin(), b.end()), b.end());
      |             ^~~~~~
0_0_39560248_9789.cpp:82:17: error: 'upper_bound' was not declared in this scope
   82 |         int r = upper_bound(b.begin(), b.end(), a[i] + k) - b.begin();
      |                 ^~~~~~~~~~~