Lua华容道可解：逆序数的奇偶判定

local function inversions(t)
    local inv = 0
    for i = 1, #t do
        for j = i + 1, #t do
            if t[i] > t[j] and t[j] ~= 0 then
                inv = inv + 1
            end
        end
    end
    return inv
end

local function solvable(t, width)
    local inv = inversions(t)
    if width % 2 == 1 then
        return inv % 2 == 0
    end
    local blankRow = 0
    for i = #t, 1, -1 do
        blankRow = blankRow + 1
        if t[i] == 0 then break end
    end
    return (inv + blankRow) % 2 == 1
end
local p = getplayerbyname("klotski01")
sendmsg(p, 1, "可解 " .. tostring(
    solvable({1, 2, 3, 4, 5, 6, 8, 7, 0}, 3)))