【入门夯实】字符串reverse的应用：反向遍历与回文判断

local function isPalindromebad(s)
    return s == string.reverse(s)
end
isPalindromebad("上海自来水来自海上")

local function isPalindromeASCII(s)
    return s == string.reverse(s)
end
local function isPalindromeUTF8(s)
    local chars = {}
    for ch in string.gmatch(s, "[\128-\191]*[\194-\244]") do
        chars[#chars + 1] = ch
    end
    local rev = {}
    for i = #chars, 1, -1 do
        rev[#rev + 1] = chars[i]
    end
    return table.concat(chars) == table.concat(rev)
end
print(isPalindromeASCII("abcba"))

local function findLast(s, sub)
    local rs = string.reverse(s)
    local pos = string.find(rs, sub, 1, true)
    if pos == nil then
        return nil
    end
    return #s - pos - #sub + 2
end