foo.cc: In function 'void build(int, int, int)':
foo.cc:16:14: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid = l + r >> 1;
            ~~^~~
foo.cc: In function 'int qm(int, int, int)':
foo.cc:26:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid = tree[k].l + tree[k].r >> 1, mx = 0;
            ~~~~~~~~~~^~~~~~~~~~~
foo.cc: In function 'int qs(int, int, int)':
foo.cc:35:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid = tree[k].l + tree[k].r >> 1, ans = 0;
            ~~~~~~~~~~^~~~~~~~~~~
foo.cc: In function 'void change(int, int, int)':
foo.cc:48:22: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int mid = tree[k].l + tree[k].r >> 1;
            ~~~~~~~~~~^~~~~~~~~~~
foo.cc: In function 'int findl(int)':
foo.cc:62:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         int mid = l + r >> 1;
                   ~~^~~
foo.cc: In function 'int findr(int)':
foo.cc:73:21: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         int mid = l + r >> 1;
                   ~~^~~

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