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Title Description
Given two strings s and t, t write a function to determine whether the ectopic letters of the word s.
Example 1:
Input: s = "anagram", t = "nagaram"
Output: true
Example 2:
Input: s = "rat", t = "car"
Output: false
Description:
You can assume that the string contains only lowercase letters.
answer
Understanding, mainly refers to a hash more correspondence relationship, not necessarily bound by a particular data structure. The main question uses hashing and sorting method.
Hash (java)
Idea: As all the possible space is not large, so consider using a hash table method, maintaining an array of all the letters of the location, the original array plus a case of a letter, a letter met the target array minus one. Finally, check whether the array elements are zero.
public boolean isAnagram(String s, String t) {
if (s.length() != t.length()) {
return false;
}
int[] counter = new int[26];
for (int i = 0; i < s.length(); i++) {
counter[s.charAt(i) - 'a']++;
counter[t.charAt(i) - 'a']--;
}
for (int count : counter) {
if (count != 0) {
return false;
}
}
return true;
}
Complexity Analysis
- Time complexity: O (n)
- Space complexity: O (1)
Sorting (java)
Thinking: two strings directly into the array is sorted, and then check the consistency or not.
public boolean isAnagram(String s, String t) {
if (s.length() != t.length()) {
return false;
}
char[] str1 = s.toCharArray();
char[] str2 = t.toCharArray();
Arrays.sort(str1);
Arrays.sort(str2);
return Arrays.equals(str1, str2);
}
- Time complexity: O (n)
- Space complexity: O (n)
