/in/foo.cc: In function 'int main()':
/in/foo.cc:14:41: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if(yw[imin]<yw[j] || yw[imin]==yw[j] && sx[imin]<sx[j]) swap(imin,j);
                         ~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~