foo.cc: In function 'bool operator<(const point&, const point&)':
foo.cc:16:40: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
         return a.x < b.x || a.x == b.x && a.y < b.y;
                             ~~~~~~~~~~~^~~~~~~~~~~~
foo.cc: In function 'int main()':
foo.cc:102:35: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
             rec[i].y == rec[st].y && rec[i].x < rec[st].x) {
             ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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