把数字1,2,3,·······2n-1,2n分为两组,每组有n个数,设这两组数a1,a2,a3····an;b1,b2,b3,····bn满足:

问题描述:

把数字1,2,3,·······2n-1,2n分为两组,每组有n个数,设这两组数a1,a2,a3····an;b1,b2,b3,····bn满足:
a1bn
试证明:|a1-b1|+|a2-b2|+|a3-b3|······|an-bn|=n^2

你想啊,肯定存在一个i使得 ai>bi 而a(i-1)