Java排列组合算法

1、全排列算法

import java.util.ArrayList;/** * 全排列算法 *  */public class Arrange {private int total = 0;private ArrayList arrangeList = new ArrayList();public Arrange() {}private void swap(String list[], int k, int i) {String c3 = list[k];list[k] = list[i];list[i] = c3;}public void perm(String list[], int k, int m) {if (k > m) {StringBuffer sb = new StringBuffer();for (int i = 0; i <= m; i++) {sb.append(list[i]).append(",");}if (sb.length()>0) {sb.setLength(sb.length()-1);}arrangeList.add(sb.toString());total++;} else {for (int i = k; i <= m; i++) {swap(list, k, i);perm(list, k + 1, m);swap(list, k, i);}}}public int getTotal() {return total;}public ArrayList getArrangeList() {return arrangeList;}public static void main(String args[]) {String list[] = { "1", "2", "3", "4", "5" };Arrange ts = new Arrange();ts.perm(list, 0, list.length-1);for (int i = 0; i < ts.getArrangeList().size(); i++) {System.out.println(ts.getArrangeList().get(i));}System.out.println("total:" + ts.total);}}

 2、组合算法

import java.util.ArrayList;import java.util.BitSet;public class Combination {private ArrayList combList= new ArrayList();public void mn(String[] array, int n) {int m = array.length;if (m < n)throw new IllegalArgumentException("Error   m   <   n");BitSet bs = new BitSet(m);for (int i = 0; i < n; i++) {bs.set(i, true);}do {printAll(array, bs);} while (moveNext(bs, m));}/** * 1、start 第一个true片段的起始位，end截止位 * 2、把第一个true片段都置false * 3、数组从0下标起始到以第一个true片段元素数量减一为下标的位置都置true * 4、把第一个true片段end截止位置true *  * @param bs 数组是否显示的标志位 * @param m 数组长度 * @return boolean 是否还有其他组合 */private boolean moveNext(BitSet bs, int m) {int start = -1;while (start < m)if (bs.get(++start))break;if (start >= m)return false;int end = start;while (end < m)if (!bs.get(++end))break;if (end >= m)return false;for (int i = start; i < end; i++)bs.set(i, false);for (int i = 0; i < end - start - 1; i++)bs.set(i);bs.set(end);return true;}/** * 输出生成的组合结果 *  * @param array 数组 * @param bs 数组元素是否显示的标志位集合 */private void printAll(String[] array, BitSet bs) {StringBuffer sb = new StringBuffer();for (int i = 0; i < array.length; i++)if (bs.get(i)) {sb.append(array[i]).append(',');}sb.setLength(sb.length() - 1);combList.add(sb.toString());}public ArrayList getCombList() {return combList;}public static void main(String[] args) throws Exception {Combination comb = new Combination();comb.mn(new String[]{"1","2","3","4","5","6"}, 3);for (int i = 0; i < comb.getCombList().size(); i++) {System.out.println(comb.getCombList().get(i));String[] list = comb.getCombList().get(i).split(",");Arrange ts = new Arrange();ts.perm(list, 0, list.length-1);for (int j = 0; j < ts.getArrangeList().size(); j++) {System.out.println("/u0009"+ts.getArrangeList().get(j));}}}}

3、调用排列组合算法工具类

import java.util.ArrayList;public class ArrangeCombine {public static ArrayList getArrangeOrCombine(String[] args,int n, boolean isArrange) throws Exception{if (args.length<=0) {throw new Exception("array.length<=0");}if (n>args.length) {throw new Exception(" n>array.length");}Combination comb = new Combination();comb.mn(args, n);if (!isArrange) {return comb.getCombList();}ArrayList arrangeList = new ArrayList();for (int i = 0; i < comb.getCombList().size(); i++) {String[] list = comb.getCombList().get(i).split(",");Arrange ts = new Arrange();ts.perm(list, 0, list.length-1);for (int j = 0; j < ts.getArrangeList().size(); j++) {arrangeList.add(ts.getArrangeList().get(j));}}return arrangeList;}public static void main(String[] args) {try {ArrayList arrangeOrCombine = ArrangeCombine.getArrangeOrCombine(new String[]{"1","2","3","4","5","6"}, 3, false);ArrayList arrangeOrCombine2 = ArrangeCombine.getArrangeOrCombine(new String[]{"1","2","3","4","5","6"}, 3, true);for (int i = 0; i < arrangeOrCombine.size(); i++) {System.out.println(arrangeOrCombine.get(i));}System.out.println("Total:"+arrangeOrCombine.size());System.out.println("=============================");for (int i = 0; i < arrangeOrCombine2.size(); i++) {System.out.println(arrangeOrCombine2.get(i));}System.out.println("Total:"+arrangeOrCombine2.size());} catch (Exception e) {e.printStackTrace();}}}