foo.cc: In function ‘void solve()’:
foo.cc:3:30: warning: unnecessary parentheses in declaration of ‘i’ [-Wparentheses]
    3 | #define rep(s, x, y) for (ll (s) = (x); (s) < (y); (s)++)
      |                              ^~~
foo.cc:22:5: note: in expansion of macro ‘rep’
   22 |     rep(i, 0, n) {
      |     ^~~
foo.cc:3:30: note: remove parentheses
    3 | #define rep(s, x, y) for (ll (s) = (x); (s) < (y); (s)++)
      |                              ^~~
foo.cc:22:5: note: in expansion of macro ‘rep’
   22 |     rep(i, 0, n) {
      |     ^~~