��场风暴中心（</span><span style="line-height: 150%">xi,yi</span><span style="line-height: 150%">）的欧几里德距离。注意，地球外没有城市，金融危机也不会爆发到地球外面</span><span style="line-height: 150%">XD</span><span style="line-height: 150%">。</span></span></div>
<div style="text-indent: 27pt; line-height: 150%"><span style="font-size: medium"><span style="line-height: 150%">小</span><span style="line-height: 150%">L</span><span style="line-height: 150%">希望