MTRIAREA  Maximum Triangle Area
English  Vietnamese 
Given n distinct points on a plane, your task is to ﬁnd the triangle that have the maximum area, whose vertices are from the given points.
Input
The input consists of several test cases. The ﬁrst line of each test case contains an integer n, indicating the number of points on the plane. Each of the following n lines contains two integer xi and yi, indicating the ith points. The last line of the input is an integer −1, indicating the end of input, which should not be processed. You may assume that 1 ≤ n ≤ 50000 and −10^4 ≤ xi, yi ≤ 10^4 for all i = 1 . . . n.
Sample Input 3 3 4 2 6 2 7 5 2 6 3 9 2 0 8 0 6 5 1
Output
For each test case, print a line containing the maximum area, which contains two digits after the decimal point. You may assume that there is always an answer which is greater than zero.
Sample output 0.50 27.00
hide comments
Naman Goyal:
20140726 10:57:21
Don't use float, you'll get WA. 

hit_code:
20140613 17:57:17
some more test case? 

:D:
20121116 07:10:37
Yes, they seem to rule each other out. Well, strictly speaking 1 <= n <= 50000, doesn't require some n to be 1 or 2, but ranges shouldn't be that unnecessary invalid. 

uberness132:
20121116 03:13:50
how can n < 3? "You may assume that 1 ≤ n ≤ 50000 " and "You may assume that there is always an answer which is greater than zero." 

Cong Liu:
20101124 09:46:44
My algo is O(n) which I think should be right but not yet proofed. Last edit: 20090415 15:01:38 

[Trichromatic] XilinX:
20101124 09:46:44
O(n^2)(Of course, with many optimizations) CAN get Accepted! Last edit: 20090326 03:01:49 
Added by:  ~!(*(@*!@^& 
Date:  20090223 
Time limit:  0.170s0.712s 
Source limit:  50000B 
Memory limit:  1536MB 
Cluster:  Cube (Intel G860) 
Languages:  All except: ERL JS PERL 6 
Resource:  Pre Shanghai 2004 