第三题，最简单暴力解，连缓存都没用，可以过

const readline = require('readline')
const log = console.log.bind(console)
const rl = readline.createInterface({
    input: process.stdin,
    output: process.stdout
})

rl.on('line', function(line){
    const str = line.trim()
    const result = handle(str)
    // var output = result ? 1 : 0
    log(result)
});

const valid = function(checkString) {
    var s = checkString
    var len = s.length
    var odd = len % 2 === 1
    var subLen = Math.floor(len / 2)
    var t1 = s.slice(0, subLen)
    var t2 = odd ? s.slice(subLen + 1) : s.slice(subLen)
    t2 = t2.split('').reverse().join('')
    // log('t', t1, t2)
    return t1 === t2
}

const handle = function(str) {
    var s = str
    var arr = s.split('')
    var set = new Set(arr)
    set = [...set]
    var result = 0
    for(var k = 0; k < set.length; k++) {
        var c = set[k]
        var t = c + s
        if (valid(t)) {
            return 1
        }
    }
    for(var i = 0; i < s.length; i++) {
        for(var j = 0; j < set.length; j++) {
            var v = set[j]
            var temp = s.slice(0, i + 1) + v + s.slice(i + 1)
            if (valid(temp)) {
                return 1
            }
        }
    }
    return 0
}

btw，前端为何不用node（