/in/foo.cc: In function 'void build(int, int, int)':
/in/foo.cc:22:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int m=l+r>>1;
        ~^~
/in/foo.cc: In function 'void update(int, int, int, int, int)':
/in/foo.cc:33:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int m=l+r>>1;
        ~^~
/in/foo.cc: In function 'void DFS(int, int, int)':
/in/foo.cc:45:9: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  int m=l+r>>1;
        ~^~