A.隊(duì)數(shù) B.隊(duì)數(shù)+1 C.隊(duì)數(shù)-1 D.隊(duì)數(shù)×(隊(duì)數(shù)-1)÷2
A.隊(duì)數(shù) B.隊(duì)數(shù)-1 C.隊(duì)數(shù)+1 D.隊(duì)數(shù)×(隊(duì)數(shù)-1)÷2