Online JudgeProblem SetAuthorsOnline ContestsUser
Web Board
Home Page
F.A.Qs
Statistical Charts
Problems
Submit Problem
Online Status
Prob.ID:
Register
Update your info
Authors ranklist
 Current Contest
Past Contests
Scheduled Contests
Award Contest
User ID:
Password:
  Register

自己推公式很简单的 将总人数的分成两部分 然后Cn2加起来就行 高中时的排列问题

Posted by i_love_c at 2007-02-26 07:47:21 on Problem 1455 
若为odd if(num%2){
			value=num/2;
			printf("%d\n",value*(value-1)/2+(value+1)*value/2);
		}

若为even  printf("%d\n",(num/2)*(num/2-1));//这里是除以2后再乘以2 因为是偶数所以是对称的
Followed by:
Post your reply here:
User ID:
Password:
Title:

Content:

Home Page   Go Back  To top

All Rights Reserved 2003-2013 Ying Fuchen,Xu Pengcheng,Xie Di
Any problem, Please Contact Administrator