BlackJack

2428: [HAOI2006]均分数据 Time Limit: 5 Sec  Memory Limit: 128 MB Submit: 2183  Solved: 680 [Submit][Status][Discuss] Description 已知N个正整数：A1、A2、……、An 。今要将它们分成M组，使得各组数据的数值和最平均，即各组的均方差最小。均方差公式如下： ,其中

3680: 吊打XXX Time Limit: 10 Sec  Memory Limit: 128 MBSec  Special Judge Submit: 2743  Solved: 1006 [Submit][Status][Discuss] Description gty又虐了一场比赛，被虐的蒟蒻们决定吊打gty。gty见大势不好机智的分出了n个分身，但还是被人多势众的蒟蒻抓

2210: Pku1379 Run Away Time Limit: 1 Sec  Memory Limit: 259 MB Submit: 141  Solved: 54 [Submit][Status][Discuss] Description One of the traps we will encounter in the Pyramid is located in the