/in/foo.cc: In function 'int main()':
/in/foo.cc:13:36: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
    if(yw[j]>yw[j-1]||yw[j]==yw[j-1]&&sx[j]>sx[j-1])
                      ~~~~~~~~~~~~~~^~~~~~~~~~~~~~~