java变位词_Java程序检查字符串是否是变位词

怼烎@ 2022-11-03 00:42 128阅读 0赞

字符串变位词检查：有多种方法来查找两个字符串是变位词还是非变位词。经典的方法是获取每个字符串的字符数组，然后比较它们，如果两个字符数组都相等，那么字符串就是变位词。但在进行比较之前，请确保两个字符串的大小写相同(例如小写或大写)，并且对字符数组进行排序，因为equals数组方法，只有当数组包含相同的长度，并且每个索引具有相同的字符时才返回true。

为了简单起见，我省略了检查字符串是否为空，并将其转换为大写或小写，如果需要，可以执行此操作。如果面试官要求你写生产质量代码，那么我建议你一定要做这些检查，并为空字符串抛出IllegalArgumentException，否则你只需返回false。我个人更喜欢返回false而不是抛出异常，类似于equals()方法。不管怎样，这里有三种方法来检查两个字符串是否是变位词。我还包括了一个JUnit测试来验证各种包含变位词和非变位词的字符串。

import java.util.Arrays;

/\*\*

\* Java program - String Anagram Example.

\* This program checks if two Strings are anagrams or not

\* @author Javin Paul

\*/public class AnagramCheck \{/\*

\* One way to find if two Strings are anagram in Java. This method

\* assumes both arguments are not null and in lowercase.

\* @return true, if both String are anagram

\*/public static boolean isAnagram(String word, String anagram)\{

if(word.length() != anagram.length())\{

return false;

char\[\] chars = word.toCharArray();

for(char c : chars)\{

int index = anagram.indexOf(c);

if(index != -1)\{

anagram = anagram.substring(0,index) + anagram.substring(index +1, anagram.length());

\}else\{

return false;

return anagram.isEmpty();

\}/\*

\* Another way to check if two Strings are anagram or not in Java

\* This method assumes that both word and anagram are not null and lowercase

\* @return true, if both Strings are anagram.

\*/public static boolean iAnagram(String word, String anagram)\{

char\[\] charFromWord = word.toCharArray();

char\[\] charFromAnagram = anagram.toCharArray();

Arrays.sort(charFromWord);

Arrays.sort(charFromAnagram);

return Arrays.equals(charFromWord, charFromAnagram);

public static boolean checkAnagram(String first, String second)\{

char\[\] characters = first.toCharArray();

StringBuilder sbSecond = new StringBuilder(second);

for(char ch : characters)\{

int index = sbSecond.indexOf(""+ ch);

if(index != -1)\{

sbSecond.deleteCharAt(index);

\}else\{

return false;

return sbSecond.length()==0 ? true : false;

字符串变位词exmaple的JUnit测试用例

这是我们对anagramcheck类的三个方法的JUnit测试，我们实际上用类似的输入集测试了所有方法。import org.junit.Test;

import static org.junit.Assert.\*;

/\*\*

\* JUnit test class to test various anagram program for various String input.

\*/public class StringAnagramTest \{

@Test

public void testIsAnagram() \{

assertTrue(AnagramCheck.isAnagram("word","wrdo"));

assertTrue(AnagramCheck.isAnagram("mary","army"));

assertTrue(AnagramCheck.isAnagram("stop","tops"));

assertTrue(AnagramCheck.isAnagram("boat","btoa"));

assertFalse(AnagramCheck.isAnagram("pure","in"));

assertFalse(AnagramCheck.isAnagram("fill","fil"));

assertFalse(AnagramCheck.isAnagram("b","bbb"));

assertFalse(AnagramCheck.isAnagram("ccc","ccccccc"));

assertTrue(AnagramCheck.isAnagram("a","a"));

assertFalse(AnagramCheck.isAnagram("sleep","slep"));

@Test

public void testIAnagram() \{

assertTrue(AnagramCheck.iAnagram("word","wrdo"));

assertTrue(AnagramCheck.iAnagram("boat","btoa"));

assertFalse(AnagramCheck.iAnagram("pure","in"));

assertFalse(AnagramCheck.iAnagram("fill","fil"));

assertTrue(AnagramCheck.iAnagram("a","a"));

assertFalse(AnagramCheck.iAnagram("b","bbb"));

assertFalse(AnagramCheck.iAnagram("ccc","ccccccc"));

assertFalse(AnagramCheck.iAnagram("sleep","slep"));

@Test

public void testcheckAnagram() \{

assertTrue(AnagramCheck.checkAnagram("word","wrdo"));

assertFalse(AnagramCheck.checkAnagram("b","bbb"));

assertFalse(AnagramCheck.checkAnagram("ccc","ccccccc"));

assertTrue(AnagramCheck.checkAnagram("a","a"));

assertFalse(AnagramCheck.checkAnagram("sleep","slep"));

assertTrue(AnagramCheck.checkAnagram("boat","btoa"));

assertFalse(AnagramCheck.checkAnagram("pure","in"));

assertFalse(AnagramCheck.checkAnagram("fill","fil"));

Output

Testsuite: StringAnagramTest

Tests run: 3, Failures: 0, Errors: 0, Time elapsed: 0.094 sec

我们的anagramcheck类包含3个静态方法来验证字符串是否为变位词。首先，获取第一个字符串的字符数组并循环遍历它，然后在第二个字符串中查找该字符，并使用substring方法删除它。如果第二个字符串不包含字符，则立即返回false。测试结束时，如果第二个字符串为空，则两个字符串都是变位词，因为它们包含相同的字符集。为了提高性能，我们在这个方法的最开始就检查了长度，因为两个长度不同的字符串不能互相变位。第三个方法与第一个方法完全相同，只是它使用StringBuilder的DeleteCharat(int index)方法删除字符。