BISHI29 小红的排列构造①

求解代码publicstaticvoidmain(String[]args)throwsIOException{BufferedReaderbrnewBufferedReader(newInputStreamReader(System.in));StreamTokenizerinnewStreamTokenizer(br);PrintWriteroutnewPrintWriter(newOutputStreamWriter(System.out));in.nextToken();intn(int)in.nval;int[]arrnewint[n];if(n2){out.println(-1);}else{arr[0]3;// 第一个元素固定为3for(inti1;in;i){arr[i]i1;//从第2个元素开始值为「索引1」}arr[2]1;// 第三个元素强制改为1for(inti0;in;i){out.print(arr[i](in-1?: ));}}out.flush();out.close();br.close();}