cf B. The Fibonacci Segment

http://codeforces.com/contest/365/problem/B

 1 #include <cstdio>
 2 #include <cstring>
 3 #include <algorithm>
 4 #define maxn 200010
 5 #define LL __int64
 6 using namespace std;
 7 
 8 int n;
 9 LL a[maxn];
10 
11 int main()
12 {
13     while(scanf("%d",&n)!=EOF)
14     {
15         for(int i=1; i<=n; i++)
16         {
17             scanf("%I64d",&a[i]);
18         }
19         int max1=min(2,n);
20         int len=2;
21         for(int i=3; i<=n; i++)
22         {
23             if(a[i]==a[i-2]+a[i-1])
24             {
25                 len++;
26                 max1=max(max1,len);
27             }
28             else len=2;
29         }
30         printf("%d
",max1);
31     }
32     return 0;
33 }

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