Lua组合数：连乘商式的滚动求值

local function fact(n)
    local r = 1
    for i = 2, n do r = r * i end
    return r
end
local function combFact(n, k)
    return fact(n) / (fact(k) * fact(n - k))
end

local function comb(n, k)
    if k > n - k then k = n - k end
    local r = 1
    for i = 1, k do
        r = r * (n - k + i) / i
    end
    return r
end
local p = getplayerbyname("comb01")
sendmsg(p, 1, "C(8,3)=" .. comb(8, 3)
    .. "，C(30,10)=" .. comb(30, 10))