foo.cc: In member function 'void tree::build(int, int, int)':
foo.cc:25:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   25 |         int mid = L + R >> 1;
      |                   ~~^~~
foo.cc: In member function 'void tree::modify(int, int, int, int)':
foo.cc:39:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   39 |         int mid = nd[p].L + nd[p].R >> 1;
      |                   ~~~~~~~~^~~~~~~~~
foo.cc: In member function 'void tree::query(int, int)':
foo.cc:60:27: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   60 |         int mid = nd[p].L + nd[p].R >> 1;
      |                   ~~~~~~~~^~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:82:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   82 |     scanf("%d %d", &n, &q);
      |     ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:84:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   84 |         scanf("%lld", &a[i]);
      |         ~~~~~^~~~~~~~~~~~~~~
foo.cc:91:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   91 |         scanf("%d", &op);
      |         ~~~~~^~~~~~~~~~~
foo.cc:94:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   94 |             scanf("%d %d %d", &l, &r, &v);
      |             ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
foo.cc:98:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   98 |             scanf("%d %d", &x, &v);
      |             ~~~~~^~~~~~~~~~~~~~~~~
foo.cc:104:18: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  104 |             scanf("%d", &x);
      |             ~~~~~^~~~~~~~~~

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