Step by Step solution about How to resolve the algorithm Balanced brackets step by step in the Julia programming language

The provided Julia code defines a function balancedbrackets to check if a given string containing square brackets ([, ]) is balanced, meaning that for every opening bracket, there is a corresponding closing bracket. Here's how the code works:

1. Function Definition:

   • balancedbrackets(str::AbstractString): This is the main function that takes a string str containing square brackets as input and returns true if the brackets are balanced and false otherwise.

2. Loop to Check Balance:

   • The code iterates through each character c in the input string str.
   • If c is an opening bracket ([), it increments a counter i by 1.
   • If c is a closing bracket (]), it decrements the counter i by 1.
   • After processing each character, it checks if the counter i becomes negative. If i is negative, it means there are more closing brackets than opening brackets, so it returns false.

3. Final Check:

   • After iterating through the entire string, it checks if the counter i is equal to 0. If i is 0, it means that the string has the same number of opening and closing brackets, so it returns true. Otherwise, it returns false.

4. Testing the Function:

   • The code generates a list of test strings by generating strings with different combinations of opening and closing brackets.
   • For each test string, it calls the balancedbrackets function and stores the result in a tuple along with the test string.
   • Then, it iterates through the tuples and prints the test string and whether it passed or failed the balance check.

5. Alternative Function:

   • The second balancedbrackets function uses a more concise approach using Julia's foldl function to accumulate the difference between opening and closing brackets while iterating through the string characters. If the final result is 0, the brackets are balanced, and it returns true; otherwise, it returns false.

using Printf

function balancedbrackets(str::AbstractString)
    i = 0
    for c in str
        if c == '[' i += 1 elseif c == ']' i -=1 end
        if i < 0 return false end
    end
    return i == 0
end

brackets(n::Integer) = join(shuffle(collect(Char, "[]" ^ n)))

for (test, pass) in map(x -> (x, balancedbrackets(x)), collect(brackets(i) for i = 0:8))
    @printf("%22s%10s\n", test, pass ? "pass" : "fail")
end


balancedbrackets(str::AbstractString) = foldl((x, y) -> x < 0 ? -1 : x + y, collect((x == '[') - (x == ']') for x in str), init = 0) == 0