![「BZOJ3479」[Usaco2014 Mar] Watering the Fields](http://hzwer.com/wp-content/themes/ly/image/image_post/2014-12-10_12-22-53.jpg)
Description Duetoalackofrain,FarmerJohnwantstobuildanirrigationsystemtosendwaterbetweenhisNfields(1<=N<=2000).Eachfieldiisdescribedbyadistinctpoint(xi,yi)inthe2Dplane,with0<=xi,yi<=1000.ThecostofbuildingawaterpipebetweentwofieldsiandjisequaltothesquaredEuclideandistancebetweenthem:(xi-xj)^2+(yi-yj)^2FJwouldliketobuildaminimum-costsystemofpipessothatallofhisfieldsarelinkedt...
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