Javascript 程序检查两个字符串是否互为 Anagram

编写一个函数来检查两个给定的字符串是否是彼此的字谜。一个字符串的变位词是另一个包含相同字符的字符串，只是字符的顺序可以不同。例如，“abcd”和“dabc”是彼此的字谜。

我们强烈建议您单击此处并进行练习，然后再继续使用解决方案。

方法一（使用排序）：

1. 对两个字符串进行排序
2. 比较排序后的字符串

下面是上述思想的实现：

Javascript

// JavaScript program to check whether
// two strings are anagrams of each other
 
// Function to check whether two strings
// are anagram of each other
function areAnagram(str1,str2)
{
    // Get lengths of both strings
    let n1 = str1.length;
    let n2 = str2.length;
   
    // If length of both strings is not
    // same, then they cannot be anagram
    if (n1 != n2)
        return false;
   
    // Sort both strings
    str1.sort();
    str2.sort()
   
    // Compare sorted strings
    for (let i = 0; i < n1; i++)
        if (str1[i] != str2[i])
            return false;
   
    return true;
}
     
// Driver Code
let str1=['t', 'e', 's', 't'];
let str2=['t', 't', 'e', 'w'];
     
// Function Call
if (areAnagram(str1, str2))
    document.write(
    "The two strings are" +
    " anagram of each other<br>");
else
    document.write(
    "The two strings are not" +
    " anagram of each other<br>");
// This code is contributed by rag2127

输出：

The two strings are not anagram of each other

时间复杂度： O(nLogn)

方法2（计数字符）：
此方法假定两个字符串中可能的字符集都很小。在下面的实现中，假设字符使用 8 位存储，可能有 256 个字符。

1. 为两个字符串创建大小为 256 的计数数组。将计数数组中的所有值初始化为 0。
2. 遍历两个字符串的每个字符并增加相应计数数组中的字符计数。
3. 比较计数数组。如果两个计数数组相同，则返回 true。

下面是上述思想的实现：

Javascript

// Javascript program to check if two
// strings are anagrams of each other
let NO_OF_CHARS = 256;
 
/* Function to check whether two strings
   are anagram of each other */
function areAnagram(str1, str2)
{
    // Create 2 count arrays and initialize
    // all values as 0
    let count1 = new Array(NO_OF_CHARS);
    let count2 = new Array(NO_OF_CHARS);
    for(let i = 0; i < NO_OF_CHARS; i++)
    {
        count1[i] = 0;
        count2[i] = 0;
    }
         
    let i;
  
    // For each character in input strings,
    // increment count in the corresponding
    // count array
    for (i = 0; i < str1.length &&
         i < str2.length; i++)
    {
        count1[str1[i].charCodeAt(0)]++;
        count2[str1[i].charCodeAt(0)]++;
    }
  
    // If both strings are of different length.
    // Removing this condition will make the
    // program fail for strings like "aaca"
    // and "aca"
    if (str1.length != str2.length)
        return false;
  
    // Compare count arrays
    for (i = 0; i < NO_OF_CHARS; i++)
    if (count1[i] != count2[i])
        return false;
  
    return true;
}
 
// Driver code
let str1 =
("geeksforgeeks").split("");
let str2 =
("forgeeksgeeks").split("");
  
// Function call
if (areAnagram(str1, str2))
    document.write(
    "The two strings are" +
    "anagram of each other<br>");
else
    document.write(
    "The two strings are not" +
    " anagram of each other<br>");
// This code is contributed by avanitrachhadiya2155

输出：

The two strings are anagram of each other

方法3（使用一个数组计算字符）：
上述实现可以进一步只使用一个计数数组而不是两个。我们可以为 str1 中的字符递增 count 数组中的值，为 str2 中的字符递减。最后，如果所有计数值都是 0，那么这两个字符串是彼此的字谜。感谢Ace提出此优化建议。

Javascript

// Javascript program to check if two strings
// are anagrams of each other
let NO_OF_CHARS = 256;
 
// Function to check if two strings
// are anagrams of each other
function areAnagram(str1, str2)
{
    // Create a count array and initialize
    // all values as 0
    let count = new Array(NO_OF_CHARS);
    for(let i = 0; i < NO_OF_CHARS; i++)
    {
        count[i] = 0;
    }
    let i;
  
    // For each character in input strings,
    // increment count in the corresponding
    // count array
    for(i = 0; i < str1.length; i++)
    {
        count[str1[i].charCodeAt(0) -
              'a'.charCodeAt(0)]++;
        count[str2[i].charCodeAt(0) -
              'a'.charCodeAt(0)]--;
    }
  
    // If both strings are of different
    // length. Removing this condition
    // will make the program fail for
    // strings like "aaca" and "aca"
    if (str1.length != str2.length)
        return false;
  
    // See if there is any non-zero
    // value in count array
    for(i = 0; i < NO_OF_CHARS; i++)
    if (count[i] != 0)
    {
        return false;
    }
    return true;
}
 
// Driver code
let str1 =
"geeksforgeeks".split("");
let str2 =
"forgeeksgeeks".split("");
 
// Function call
if (areAnagram(str1, str2))
    document.write(
    "The two strings are " +
    "anagram of each other");
else
    document.write(
    "The two strings are " +
    "not anagram of each other");
// This code is contributed by unknown2108.

输出：

The two strings are anagram of each other

时间复杂度： O(n)

有关详细信息，请参阅关于检查两个字符串是否是彼此的字谜的完整文章！