foo.cc: In function 'int build(int, int, int, int)':
foo.cc:30:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         int mid=l+r>>1;
                 ~^~
foo.cc: In function 'int find(int, int, int, int, int)':
foo.cc:39:48: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
         int now=sumv[le[u2]]-sumv[le[u1]],mid=l+r>>1;
                                               ~^~
foo.cc: In function 'int main()':
foo.cc:53:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
             mid=l+r>>1;
                 ~^~

自豪的采用HydroJudge(https://github.com/hydro-dev/Hydro)进行评测。