0-1-2-3-4-5-.........-(n-2)-(n-1) there are n-1 pairs as 0-1,1-2,2-3.... if we cut one pair,we can put them into 2桶,each 桶 has at least 1 if we cut k-1 pair,we can put them into K桶,each 桶 has at least 1 then we have C(n-1,k-1) ways to cut them. is this right?
【在 l*****a 的大作中提到】 : 0-1-2-3-4-5-.........-(n-2)-(n-1) : there are n-1 pairs as 0-1,1-2,2-3.... : if we cut one pair,we can put them into 2桶,each 桶 has at least 1 : if we cut k-1 pair,we can put them into K桶,each 桶 has at least 1 : then we have C(n-1,k-1) ways to cut them. : is this right?