NewYeariscominginTreeWorld!Inthisworld,asthenameimplies,therearencitiesconnectedbyn - 1roads,andforanytwodistinctcitiestherealwaysexistsapathbetweenthem.Thecitiesarenumberedbyintegersfrom1ton,andtheroadsarenumberedbyintegersfrom1ton - 1.Let'sdefined(u, v)astotallengthofroadsonthepathbetweencityuandcityv.Asanannualevent,peopleinTreeWorldrepairsexactlyoneroadperyear.Asaresult,theleng...
Devuwantstodecoratehisgardenwithflowers.Hehaspurchased n boxes,wherethe i-thboxcontains fi flowers.Allflowersinasingleboxareofthesamecolor(hencetheyareindistinguishable).Also,notwoboxeshaveflowersofthesamecolor.NowDevuwantstoselect exactly s flowersfromtheboxestodecoratehisgarden.Devuwouldliketoknow,inhowmanydifferentwayscanheselecttheflowersfromeachbox?Sincethisnumbermaybeverylarg...
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