function isPalindrome(str){let reser = str.split(&#39;&#39;).reverse().join(&#39;&#39;)return reser === str}function find(arrs,n,m){let myMap = new Map()for(let i = 0;i < m;i++){myMap.set(arrs[i],i+1)}let res = [];function backtracking(index,curstr,used){if(index === arrs.length){if(isPalindrome(curstr)){res.push({pal:curstr})}return;}for(let i= 0;i<arrs.length;i++){if(used[i]) continue;let newstr = curstr + arrs[i];let newused = [...used]newused[i] = true;backtracking(index+1,newstr,newused)if(newstr.length < 2 * m &amp;amp;&amp;amp; index < arrs.length - 1){let mid = Math.floor(newstr.length/2);let temp = newstr.slice(0,mid)+arrs[i]+newstr.slice(mid);backtracking(index+1,temp,newstr)}}}let initused = new Array(arrs.length).fill(false);backtracking(0,&#39;&#39;,initused)let orderanswer = [];for(let i = 0;i < res[0].pal.length;i += m){let nstr = res[0].pal.substring(i,i+m);let or = myMap.get(nstr)orderanswer.push(or)}// console.log(orderanswer)return orderanswer.join(&#39; &#39;)let result = find(arr,n,m)console.log(result)
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