Challenge #298 [Easy] Too many Parentheses.jl

using Combinatorics

function find_matching_pairs(s)
    l, starts = [], []
    for i in 1:length(s)
        if s[i] == "("
            push!(starts, i)
        elseif s[i] == ")"
            push!(l, (pop!(starts), i))
        end
    end
    l
end

function remove(s)
    s = split(s, "")
    pairs = find_matching_pairs(s)
    t = trues(size(s))
    
    # Set indices of parentheses enclosing nothing to false
    foreach(p -> if p[1] +1 == p[2]; t[[p...]] = false; end, pairs)
    
    # Set indices of redundant parentheses to false
    for (p1, p2) in combinations(pairs, 2)
        if p1[1] - 1 == p2[1] && p1[2] + 1 == p2[2]; t[[p1...]] = false; end
    end
    
    join(s[t])
end

inps = ["((a((bc)(de)))f)", "(((zbcd)(((e)fg))))", "ab((c))", "()", "((fgh()()()))", "()(abc())"]
outs = ["((a((bc)(de)))f)", "((zbcd)((e)fg))", "ab(c)", "", "(fgh)", "(abc)"]
@assert all(remove(inp) == out for (inp, out) in zip(inps, outs))