10119: Arithmetic Progression
Memory Limit：128 MB
Time Limit：1.000 S
Judge Style：Text Compare
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Submit：2
Solved：0
Description
“In mathematics, an arithmetic progression (AP) or arithmetic sequence is a sequence of numbers such that the difference between the consecutive terms is constant. For instance, the sequence 5, 7, 9, 11, 13, … is an arithmetic progression with common difference of 2.”
- Wikipedia
This is a quite simple problem, give you the sequence, you are supposed to find the length of the longest consecutive subsequence which is an arithmetic progression.
Input
There are several test cases. For each case there are two lines. The first line contains an integer number N (1 <= N <= 100000) indicating the number of the sequence. The following line describes the N integer numbers indicating the sequence, each number will fit in a 32bit signed integer.
Output
For each case, please output the answer in one line.
Sample Input Copy
6
1 4 7 9 11 14Sample Output Copy
3