/in/foo.cc: In function 'int main()':
/in/foo.cc:54:8: warning: unused variable 'cnt' [-Wunused-variable]
    int cnt=0;
        ^~~
/in/foo.cc:56:9: warning: variable 't1' set but not used [-Wunused-but-set-variable]
    node t1 ;t1.col= c,t1.pos = x;
         ^~
/in/foo.cc:57:9: warning: variable 't2' set but not used [-Wunused-but-set-variable]
    node t2 ; t2.col = c,t2.pos = y;
         ^~
/in/foo.cc: In function 'int find(int, int)':
/in/foo.cc:22:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^