require "table2"
local fmt = require "fmt"

local tests = {"abracadabra", "seesaw", "elk", "grrrrrr", "up", "a"}
for tests as s do
    local t = s:split(""):shuffle()
    for i = 1, #t do
        for j = 1, #t do
            if i != j and t[i] != s[j] and t[j] != s[i] then
                t[i], t[j] = t[j], t[i]
                break
            end
        end
    end
    local c = range(1, #s):count(|i| -> s[i] == t[i])
    fmt.print("%s, %s, (%d)\n", s, t:concat(""), c)
end