Python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：

Python

# Python program to check whether two 
# strings are anagrams of each other
  
# Function to check whether two strings 
# are anagram of each other
def areAnagram(str1, str2):
    # Get lengths of both strings
    n1 = len(str1)
    n2 = len(str2)
  
    # If length of both strings is not 
    # same, then they cannot be anagram
    if n1 != n2:
        return 0
  
    # Sort both strings
    str1 = sorted(str1)
    str2 = sorted(str2)
  
    # Compare sorted strings
    for i in range(0, n1):
        if str1[i] != str2[i]:
            return 0
  
    return 1
  
# Driver code
str1 = "test"
str2 = "ttew"
  
# Function Call
if areAnagram(str1, str2):
    print(
    "The two strings are anagram of each other")
else:
    print(
    "The two strings are not anagram of each other")
# This code is contributed by Bhavya Jain

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：

Python

# Python program to check if two strings 
# are anagrams of each other
NO_OF_CHARS = 256
  
# Function to check whether two strings 
# are anagram of each other
def areAnagram(str1, str2):
  
    # Create two count arrays and initialize 
    # all values as 0
    count1 = [0] * NO_OF_CHARS
    count2 = [0] * NO_OF_CHARS
  
    # For each character in input strings, 
    # increment count in the corresponding 
    # count array
    for i in str1:
        count1[ord(i)] += 1
  
    for i in str2:
        count2[ord(i)] += 1
  
    # If both strings are of different length. 
    # Removing this condition will make the 
    # program fail for strings like "aaca" 
    # and "aca"
    if len(str1) != len(str2):
        return 0
  
    # Compare count arrays
    for i in xrange(NO_OF_CHARS):
        if count1[i] != count2[i]:
            return 0
  
    return 1
  
# Driver code
str1 = "geeksforgeeks"
str2 = "forgeeksgeeks"
  
# Function call
if areAnagram(str1, str2):
    print 
    "The two strings are anagram of each other"
else:
    print 
    "The two strings are not anagram of each other"
# This code is contributed by Bhavya Jain

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。

Python3

# Python program to check if two strings
# are anagrams of each other
NO_OF_CHARS = 256
  
# Function to check if two strings
# are anagrams of each other
def areAnagram(str1,str2):
      
    # Create a count array and initialize
    # all values as 0
    count=[0 for i in range(NO_OF_CHARS)]
    i=0
      
    # For each character in input strings,
    # increment count in the corresponding
    # count array
    for i in range(len(str1)):
        count[ord(str1[i]) - ord('a')] += 1;
        count[ord(str2[i]) - ord('a')] -= 1;
      
    # If both strings are of different
    # length. Removing this condition
    # will make the program fail for
    # strings like "aaca" and "aca"    
    if(len(str1) != len(str2)):
        return False;
      
    # See if there is any non-zero
    # value in count array
    for i in range(NO_OF_CHARS):
        if (count[i] != 0):
            return False        
      
    return True
  
# Driver code
str1="geeksforgeeks"
str2="forgeeksgeeks"
  
# Function call
if (areAnagram(str1, str2)):
    print(
    "The two strings are anagram of each other")
else:
    print(
    "The two strings are not anagram of each other")
# This code is contributed by patel2127

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！