"column"><h4 class="ui top attached block header">输入格式</h4><div class="ui bottom attached segment font-content"><div style="position: relative; overflow: hidden;"><div class=content><p>只包含4个整数，它们彼此用空格隔开，分别为xp,yp,xs,ys。并且它们的都小于10000000。</p></div></div></div></div></div><div class="row"><div class="column"><h4 class="ui top attached block header">输出格式</h4><div class="ui bottom attached segment font-content"><div style="position: relat