用Java实现用序数法生成全排列
用Java实现用序数法生成全排列
用java实现用序数法生成全排列:
- import java.io.*;
- import java.util.ArrayList;
- class Arrangement{
- public static void main(String args[]){
- Arrangement arrangement = null;
- int num = 0;//要排序的个数
- boolean flag = true;//标志位,如果用户输入的待排序个数不合法,该值一直为true
- ArrayList<String> strs = new ArrayList<String>();
- while(flag){
- try{
- num = Integer.parseInt(readDataFromConsole("请输入待排序的个数:"));
- flag = false;
- }catch(Exception e){
- System.out.println("请输入整数.");
- }
- }
- for(int i = 1; i <= num; i ++){
- strs.add(readDataFromConsole("请输入第" + i + "个字符: "));
- }
- arrangement = new Arrangement(strs.toArray(new String[]{}));
- System.out.println("排列后的数据为:");
- arrangement.sort();
- }
- private String[] str = null;
- public Arrangement(String[] s){
- this.str = s;
- }
- //从控制台读入数据
- private static String readDataFromConsole(String prompt) {
- BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
- String str = null;
- try {
- System.out.print(prompt);
- str = br.readLine();
- } catch (IOException e) {
- e.printStackTrace();
- }
- return str;
- }
- private void sort(){
- int num=str.length;
- int[] n1 = new int[num -1];
- int[] nss = new int[num];
- String[] s = new String[num];
- boolean flag = false;
- int x = 0;
- do{
- if(x == 0){//第一遍初始化
- for(int i = 0;i < num - 1;i ++){
- n1[i] = 0;
- }
- } else {//生成序数
- for(int i = 0;i < num - 1;i ++){
- if(n1[num - 2 - i] < i + 1){
- n1[num - 2 - i] ++;
- for(int j=num-1-i;j<num-1;j++){
- n1[j] = 0;
- }
- break;
- }
- }
- }
- for(int i = 0;i < num - 1;i++){
- if(n1[i] == (num - 1 - i)){
- flag = false;
- } else {
- flag = true;
- break;
- }
- }
- for(int i = 0;i < num;i++){//标记位赋初值
- nss[i] = 0;
- }
- for(int i = 0;i < num - 1;i++){//计算排列顺序并为排列后的赋值
- int hh = 0, j = 0;//记录前边总共移动的位数
- do{
- if(nss[num - 1 - hh] == 1){
- hh++;
- continue;
- } else {
- if(j == n1[i]){
- break;//每个字母距最右端未填入的位置
- } else {
- hh++;
- j++;
- }
- }
- } while(true);
- hh = num - 1 - hh;
- s[hh] = str[num-1-i];
- nss[hh] = 1;
- }
- for(int i = 0; i < num;i++){//查找空缺位
- if(nss[i] == 0) {
- s[i] = str[0];
- break;
- }
- }
- System.out.print(++x + "\t");
- for(int i = 0;i < num - 1;i++){
- System.out.print(n1[i] + "");
- }
- System.out.print("\t");
- for(int i = 0;i < num;i++){
- System.out.print(s[i] + "");
- }
- System.out.println();
- }while(flag);
- }
- }
评论暂时关闭