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The application of recursion in C algorithm can improve efficiency. Taking the Fibonacci sequence calculation as an example, the function fibonacci calls itself recursively, with a complexity of O(2^n). However, for recursive problems such as tree structures, recursion can greatly improve efficiency because the size of each problem is halved. But be careful to avoid problems such as infinite recursion and insufficient stack space. For complex recursive problems, loop or iterative methods may be more effective.
Application of Recursion in C Algorithm: Efficiency Improvement and Complexity Analysis
Introduction
Recursion is a powerful programming technique that can be used to simplify algorithms and increase efficiency. In C, recursion is implemented by a function calling itself.
Code Example
Take the following Fibonacci sequence calculation as an example:
int fibonacci(int n) { if (n <= 1) { return n; } else { return fibonacci(n - 1) + fibonacci(n - 2); } }
How to run
fibonacci
accepts an integer parameter n
, representing the n
th number in the Fibonacci sequence to be calculated. n
is less than or equal to 1, return n
directly because this is the first or second item of the sequence. n - 1
, and once with n - 2
. n
decreases to 1 or 0. Efficiency improvement
The efficiency of the recursive algorithm depends on the size of the problem type. For recursive problems such as tree structures, recursion can significantly improve efficiency because the size of each problem is reduced by half.
Complexity Analysis
The complexity of the Fibonacci sequence algorithm is O(2^n), because each recursive call will generate two new recursions transfer. For large values of n
, this results in an inefficient algorithm.
Practical case
Notes
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