java字元串組合

Ⅰ java程序如何實現對字元串的排列組合問題

import java.math.BigInteger;
import java.util.*;

public class PermutationGenerator {

private int[] a;
private BigInteger numLeft;
private BigInteger total;
public PermutationGenerator(int n) {
if (n < 1) {
throw new IllegalArgumentException("Min 1");
}
a = new int[n];
total = getFactorial(n);
reset();
}

public void reset() {
for (int i = 0; i < a.length; i++) {
a[i] = i;
}
numLeft = new BigInteger(total.toString());
}

public BigInteger getNumLeft() {
return numLeft;
}

public BigInteger getTotal() {
return total;
}

public boolean hasMore() {
return numLeft.compareTo(BigInteger.ZERO) == 1;
}

private static BigInteger getFactorial(int n) {
BigInteger fact = BigInteger.ONE;
for (int i = n; i > 1; i--) {
fact = fact.multiply(new BigInteger(Integer.toString(i)));
}
return fact;
}

public int[] getNext() {

if (numLeft.equals(total)) {
numLeft = numLeft.subtract(BigInteger.ONE);
return a;
}

int temp;

// Find largest index j with a[j] < a[j+1]

int j = a.length - 2;
while (a[j] > a[j + 1]) {
j--;
}

// Find index k such that a[k] is smallest integer
// greater than a[j] to the right of a[j]

int k = a.length - 1;
while (a[j] > a[k]) {
k--;
}

// Interchange a[j] and a[k]

temp = a[k];
a[k] = a[j];
a[j] = temp;

// Put tail end of permutation after jth position in increasing order

int r = a.length - 1;
int s = j + 1;

while (r > s) {
temp = a[s];
a[s] = a[r];
a[r] = temp;
r--;
s++;
}

numLeft = numLeft.subtract(BigInteger.ONE);
return a;

}
//程序測試入口
public static void main(String[] args) {

int[] indices;
String[] elements = { "a", "b", "c"};
PermutationGenerator x = new PermutationGenerator(elements.length);
StringBuffer permutation;

while (x.hasMore())
{
permutation = new StringBuffer("%");
indices = x.getNext();
for (int i = 0; i < indices.length; i++) {
permutation.append(elements[indices[i]]).append("%");
}
System.out.println(permutation.toString());

}
}

}

先給你一個看看！

Ⅱ java怎麼把2個字元串拼接在一起

String類的方法：

①利用運算符"+"

②public String concat(String str)進行字元串的拼接操作

StringBuffer的方法：

①public StringBuffer append(String str)將str添加到當前字元串緩沖區的字元序列的末尾

②public StringBuffer insert(int offset,String str)在當前字元串緩沖區的字元序列的下標

索引offset插入str。如果offset等於舊長度，則str添加在字元串緩沖區的尾部

如圖所示

Ⅲ java字元串合並

publicclassTest{
	publicstaticvoidmain(String[]args){
		Stringstr="0123456";
		Stringresult="";
		intid=3;
		for(inti=1;i<=id;i++){
			result+=str+i;
		}
		System.out.println(result);
	}
}

Ⅳ 在JAVA語言中怎麼樣合並字元串

	publicstaticvoidmain(String[]args){
		Strings1="abc";
		Strings2="123";
		//1
		System.out.println(s1.concat(s2));
		//2
		System.out.println(String.format("%s%s",s1,s2));
		//3
		StringBuildersbd=newStringBuilder();
		sbd.append(s1);
		sbd.append(s2);
		System.out.println(sbd.toString());
	}
	
	//別問我為什麼不用s1+s2，因為我們項目里，誰用加號連接字元串就乾死誰。

Ⅳ java字元串合並的問題

字元串值應該用equals比較相等， ==比較的是對象不是值

Ⅵ java 列出一個字元串的全字元組合情況，不考慮重復字元

package;

importjava.util.Arrays;
importjava.util.LinkedList;

publicclassRecursionSub3Sort
{
	staticintcount=0;
	staticchar[]array={'a','b','c'};
	staticLinkedList<char[]>list=newLinkedList<char[]>();
	staticint[]indexs=newint[3];
	staticintlen=array.length;

	publicstaticvoidmain(String[]args)
	{
		getSub();
		for(char[]cs:list)
		{
			System.out.println(Arrays.toString(cs));
		}
	}

	privatestaticLinkedList<char[]>getSub()
	{
		while(count<=len)
		{
			recursionSub(0,-1);
			count++;
		}
		returnlist;
	}

	privatestaticLinkedList<char[]>recursionSub(intind,intstart)
	{
		start++;
		if(start>count-1)
		{
			returnnull;
		}
		for(indexs[start]=0;indexs[start]<len;indexs[start]++)
		{
			recursionSub(0,start);
			if(start==count-1)
			{
				char[]temp=newchar[count];
				for(inti=count-1;i>=0;i--)
				{
					temp[start-i]=array[indexs[start-i]];
				}
				if(temp.length==1
						||Arrays.toString(temp).replaceAll("[\[\]\s,]","").replaceAll("(\w)\1+","$1")
							.length()!=1)
				{
					list.add(temp);
				}
			}
		}
		returnlist;
	}
}

Ⅶ java將字元串隨機打亂並且可以重新組合的方法

Scanner scanner = new Scanner(System.in);
System.out.print("輸入字元串：");
String str = scanner.nextLine();
List<Map> mapList = new ArrayList<>();
int length = str.length();
for(int i = 0;i < length;i++){
int x = (int)(Math.random()*length);
Map map = new HashMap();
map.put("sort",x);
map.put("value",str.charAt(i));
mapList.add(map);
}
System.out.print("輸出隨機變換後的結果：");
mapList.stream()
.sorted(Comparator.comparing(o -> o.get("sort").toString()))
.forEach(x-> System.out.print(x.get("value").toString()));
System.out.println();

Ⅷ java字元串數組合並 怎麼合並成一個數組

java字元串數組合並，可以使用array.復制方法，如下代碼：

packagecom.qiu.lin.he;

importjava.text.ParseException;
importjava.util.Arrays;

publicclassCeshi{
	publicstaticvoidmain(String[]args)throwsParseException{

		String[]str1={"J","a","v","a","中"};
		String[]str2={"如","何","把","兩","個","數","組","合","並","為",
				"一","個"};

		intstrLen1=str1.length;//保存第一個數組長度
		intstrLen2=str2.length;//保存第二個數組長度
		str1=Arrays.Of(str1,strLen1+strLen2);//擴容
		System.array(str2,0,str1,strLen1,strLen2);//將第二個數組與第一個數組合並
		System.out.println(Arrays.toString(str1));//輸出數組

	}
}

運行結果如下：

Ⅸ Java 字元串解析，任意組合。

publicclassTest{
	publicstaticvoidmain(String[]argv){
		Stringstr="A,B,C,D,E";
		String[]arr=str.split(",");
		Stringresult="";
		for(inti=0;i<arr.length;i++){
			for(intj=i+1;j<arr.length;j++){
				if(i<arr.length-2){
					result+=arr[i]+arr[j]+",";
				}else{
					result+=arr[i]+arr[j];
				}
			}
		}
		System.out.println(result);
	}
}

//輸出結果：

AB,AC,AD,AE,BC,BD,BE,CD,CE,DE

Ⅹ 如何在java里java字元串數組合並成一個數組

具體如下：
java字元串數組合並，可以使用array.復制方法，如下代碼：

package com.qiu.lin.he;

import java.text.ParseException;
import java.util.Arrays;

public class Ceshi {
public static void main(String[] args) throws ParseException {

String[] str1 = { "J", "a", "v", "a", "中" };
String[] str2 = { "如", "何", "把", "兩", "個", "數", "組", "合", "並", "為",
"一", "個" };

int strLen1 = str1.length;// 保存第一個數組長度
int strLen2 = str2.length;// 保存第二個數組長度
str1 = Arrays.Of(str1, strLen1 + strLen2);// 擴容
System.array(str2, 0, str1, strLen1, strLen2);// 將第二個數組與第一個數組合並
System.out.println(Arrays.toString(str1));// 輸出數組

}
}