/in/foo.cc: In function 'int main()':
/in/foo.cc:16:12: warning: suggest explicit braces to avoid ambiguous 'else' [-Wparentheses]
         if ((c[i]==')'||c[i]==']'||c[i]=='}')&&top)
            ^
/in/foo.cc:8:28: warning: 'mx' may be used uninitialized in this function [-Wmaybe-uninitialized]
     int i,j,maxn=0,s=0,x=0,mx,l;
                            ^~