foo.cc:26:17: warning: overflow in implicit constant conversion [-Woverflow]
 const int inf = 0x3f3f3f3f3f;
                 ^~~~~~~~~~~~
foo.cc: In function 'int haveBlock(int, int, int, int)':
foo.cc:73:2: warning: this 'if' clause does not guard... [-Wmisleading-indentation]
  if (x1 > x2) swap(x1, x2); if (y1 > y2) swap(y1, y2);
  ^~
foo.cc:73:29: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'if'
  if (x1 > x2) swap(x1, x2); if (y1 > y2) swap(y1, y2);
                             ^~
foo.cc: In function 'int main()':
foo.cc:96:15: error: 'build' was not declared in this scope
  getPreSum(), build();
               ^~~~~
foo.cc:98:18: warning: unused variable 'ans' [-Wunused-variable]
  for (int i = 1, ans, x1, x2, y1, y2;i <= q;i++) {
                  ^~~