Hackerrank Challenge: Staircase Problem

Exploring Swift and Dart approaches to tackle a common coding challenge—revealing insights on string manipulation and problem-solving strategies in both languages.

Today, we'll tackle HackerRank's Staircase problem using both Swift and Dart. This problem is a great way to understand how different languages handle string manipulation and pattern printing.

The Problem

Consider a staircase of size n = 4:

   #
  ##
 ###
####

The task is to create a right-aligned staircase pattern using # symbols, where the base and height are both equal to n.

Solution in Swift

Swift's string handling capabilities combined with nested loops provide a straightforward solution:

func staircase(n: Int) {
    for index in 1...n {
        for _ in 1...(n-index) {
            print(" ", terminator: "")
        }
        for _ in 1...index {
            print("#", terminator: "")
        }
        print()
    }
}

Breaking Down the Swift Solution

1. Outer loop (index in 1...n): Controls the number of rows

2. First inner loop (1...(n-index)): Prints spaces

   • Uses terminator: "" to prevent line breaks

   • Prints n-index spaces for each row

3. Second inner loop (1...index): Prints hash symbols

   • Also uses terminator: "" to keep symbols on same line

   • Prints index number of hashes

4. Final print() adds the necessary line break

The terminator: "" parameter in Swift's print function is crucial here as it prevents automatic line breaks, allowing us to build each line character by character.

Solution in Dart

Here's how we solve the same problem in Dart:

void staircase(int n) {
  for (int index = 1; index <= n; index++) {
    stdout.write(" " * (n - index));
    stdout.write("#" * index);
    print("");
  }
}

Breaking Down the Dart Solution

1. Single loop structure controlling row count

2. stdout.write() for printing without line breaks

3. Using Dart's string multiplication operator:

   • " " * (n - index) creates spaces

   • "#" * index creates hash symbols

4. print("") adds the line break

Dart's string multiplication operator * makes the code more concise compared to nested loops.

Time & Space Complexity

Both implementations have:

• Time Complexity: O(n²)

  • Swift: Due to nested loops

  • Dart: Hidden in string multiplication

• Space Complexity: O(1)

  • Both solutions print directly without storing the pattern

Conclusion

While both solutions solve the same problem, they showcase different programming paradigms:

• Swift's solution is more imperative, with explicit control over each character

• Dart's solution is more declarative, leveraging language features for string manipulation

Each approach has its merits:

• Swift's solution might be easier to modify for different patterns

• Dart's solution is more concise and potentially easier to maintain

Happy coding! 🚀

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