【高级技巧】KMP匹配：失配跳转的加速查找封装

local function buildNext(pattern)
    local next = { [1] = 0 }
    local i, j = 2, 0
    while i <= #pattern do
        if string.byte(pattern, i) == string.byte(pattern, j + 1) then
            j = j + 1
            next[i] = j
            i = i + 1
        elseif j > 0 then
            j = next[j]
        else
            next[i] = 0
            i = i + 1
        end
    end
    return next
end
local function kmpFind(text, pattern)
    local next = buildNext(pattern)
    local i, j = 1, 0
    while i <= #text do
        if j == 0 or string.byte(text, i) == string.byte(pattern, j + 1) then
            i = i + 1
            j = j + 1
            if j == #pattern then
                return i - j
            end
        elseif j > 0 then
            j = next[j]
        else
            i = i + 1
        end
    end
    return nil
end

local pos = kmpFind("沙巴克攻城战报汇总", "战报")
print(pos)