题解 | #火车进站#已画图,用树形结构进行多分支穷举

//树解法
const rl = require("readline").createInterface({ input: process.stdin });
var iter = rl[Symbol.asyncIterator]();
const readline = async () => (await iter.next()).value;
void async function () {
    // Write your code here
    while(line = await readline()){
        let trainNum = Number(line)
        let inSequence = await readline()
         inSequence = inSequence.split(' ').map(item=>Number(item))
        let stackOut = []
        let stackIn = []
        let res = []
        countSequence(stackOut,stackIn,inSequence,res)
        res.sort(function(a,b){
            return Number(a)-Number(b)
        })
        res = new Set([...res])
        res= [...res]
        res.forEach((item=>console.log(item.split('').join(' '))))
        function countSequence(stackOut,stackIn,inSequence,res){
            if(inSequence.length==0){
                while(stackIn.length!=0){
                    stackOut.push(stackIn.pop())
                }
                res.push(stackOut.map(item=>Number(item)).join(''))
                return
            }  
            stackIn.push(inSequence.shift())
            countSequence([...stackOut],[...stackIn],[...inSequence],res)
            while(stackIn.length!=0){
                stackOut.push(stackIn.pop())
                countSequence([...stackOut],[...stackIn],[...inSequence],res)
            }            
        }
    }
}()