264. Binary Strings Without Consecutive Ones
EasyDynamic ProgrammingFibonacci
Count binary strings of length n with no two consecutive 1s. Print modulo 10⁹ + 7.
Input format
A single integer n.
Output format
The count mod 10⁹ + 7.
Example 1
Input
2
Output
3
Example 2
Input
3
Output
5
Constraints
1 ≤ n ≤ 10⁶
Read input from standard input and print the answer to standard output. Your code is judged against 5 test cases, most of them hidden.
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