How does recursion differ from iterative solutions?

Recursion involves a function calling itself to solve a problem, while iteration uses a loop to repeatedly execute code.

Recursion is a method where the solution to a problem depends on solutions to smaller instances of the same problem. It involves a function calling itself while it has not yet reached a specified condition, known as the base case. Each time the function is called, the problem is broken down into smaller pieces until it can be solved directly. This approach is often used when the problem can naturally be divided into several similar smaller problems. However, recursion can be memory intensive as each recursive call requires a stack frame on the call stack.

On the other hand, iteration is a process in which a set of instructions or structures are repeatedly executed until a certain condition is met. This is typically accomplished using loops, such as for, while, and do-while loops. Iterative solutions are generally more efficient in terms of memory usage than recursive solutions, as they do not require the creation of multiple stack frames. However, they may not be as intuitive or easy to implement for certain problems, especially those that can be naturally divided into smaller sub-problems.

In terms of time complexity, both recursion and iteration can have similar efficiencies. However, the space complexity of recursion is typically higher due to the additional memory required for the stack frames. This can lead to a stack overflow error if the recursion is too deep.

In conclusion, the choice between recursion and iteration often depends on the specific problem at hand, as well as the trade-off between code readability and memory efficiency. While recursion can make code more readable and easier to understand, especially for complex problems, it can also lead to higher memory usage. Conversely, while iteration can be more memory-efficient, it may not be as intuitive or straightforward to implement for certain problems.