Do not forget that you should compare solved tasks as ints, not as strings :)

Use list to make the adjacency list and not vector.

dp[i][j]=dp[j][k]+1 where a[j]*2=a[i]+a[k] can be done using a loop.
via: http://www.geeksforgeeks.org/length-of-the-longest-arithmatic-progression-in-a-sorted-array
time O(n^2) space O(n^2)

i got this on test 08. Does anyone know the test?

Use matrix multiplication
(an+1,an)T=M(an,an-1)T

I got accepted in 0.78s using scanf instead of cin which makes me TLE

I disagree with the result in example 2 to the task 1493. According to the problem, must output "Yes", because 445219 in the summation of the digits gives 13 and 12. These numbers differ by 1. The example says "No". When checking the solution 2, the test system writes "Wrong answer". Please fix the problem or explain me the condition.

I have two ACCEPTED solution that gives different results (difference greater than 1E-5) in approximately 7.5-8% points.
Is this normal? :)

If you have access:
"Correct" solution: http://acm.timus.ru/getsubmit.aspx/6557034.cpp
Wrong solution: http://acm.timus.ru/getsubmit.aspx/6554840.cpp

Here some of this points:

-5.4 -4.0
-0.0 -4.0
5.4 -4.0
-5.4 -2.8
-2.7 -2.8
-2.4 -2.8
-2.1 -2.8
-0.6 -2.8
0.6 -2.8
2.1 -2.8
2.4 -2.8
2.7 -2.8
5.4 -2.8
-2.7 -2.5
-0.6 -2.5
0.6 -2.5
2.7 -2.5
-2.7 -2.2
2.7 -2.2
-5.1 -1.9
-4.8 -1.9
-1.8 -1.9
-0.3 -1.9
0.3 -1.9
1.8 -1.9
4.8 -1.9
5.1 -1.9
-4.2 -0.7
-2.7 -0.7
2.7 -0.7
4.2 -0.7
-1.8 -0.4
1.8 -0.4
-1.8 -0.1
1.8 -0.1
-1.8 0.2
1.8 0.2
-4.2 0.5
-2.1 0.5
-1.8 0.5
1.8 0.5
2.1 0.5
4.2 0.5
-4.2 0.8
4.2 0.8
-4.2 1.7
4.2 1.7
-5.1 2.0
5.1 2.0
-2.7 2.3
2.7 2.3
-5.4 2.6
-2.7 2.6
-2.4 2.6
-0.6 2.6
0.6 2.6
2.4 2.6
2.7 2.6
5.4 2.6
-5.4 2.9
-2.7 2.9
-2.4 2.9
-2.1 2.9
-0.6 2.9
0.6 2.9
2.1 2.9
2.4 2.9
2.7 2.9
5.4 2.9

New anti-greedy tests were added. 93 authors lost AC. If you still have AC with greedy solution, please, tell us about it here or to timus_support(at)acm.timus.ru.

What is the answer for the test case
6
1 3 2 5 4 6

Admins, please add these tests:
0.683013 0.2
0.683013 0.3
0.583013 0.4
0.583013 0.5

Just add them :)

I know this might sound stupid, but how am I supposed to know when I've finished inputting numbers? I don't see anything saying what A is equal to, so how do I know?

He guys if you can't come up with any formula...pre-computation will do the job.I could not come up with any formula so I used precomputation and AC in 0.015 sec.Good luck :)

Sorry to blunt, but I don't understand the meaning of the task.
Explain what needs to be done.

#include <cstdio>
#include <map>
std:: map <int, int> a;
int n, m, q, i, x, ans;
void solve(){
    scanf("%d", &n);
    for(i = 0 ; i < n ; i ++) scanf("%d", &x), a[x] ++;
    scanf("%d", &m);
    for(i = 0 ; i < m ; i ++){
        scanf("%d", &q);
        if(a[q]) ans ++;
    }
    printf("%d", ans);
}
int main(){
    solve();
}

Add some tests...

1000 100000000000
99999971585

10 100
86

17 500
476