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package com.lga.algorithm.tag.homework.Week_02;
import org.junit.Assert;
import org.junit.Test;
import java.util.HashMap;
import java.util.Map;
/**
* 242. 有效的字母异位词
* https://leetcode-cn.com/problems/valid-anagram/description/
*/
public class IsAnagram {
/**
* hash 统计法
*
* @param s
* @param t
* @return
*/
public boolean isAnagram_hash(String s, String t) {
if (s.length() != t.length()) return false;
Map<Character, Integer> map = new HashMap<>();
for (Character c : s.toCharArray()) {
map.put(c, map.get(c) != null ? map.get(c) + 1 : 1);
}
for (Character c : t.toCharArray()) {
if(map.containsKey(c)){
map.put(c, map.get(c) - 1);
if(map.get(c) < 0 ) return false;
}else{
return false;
};
}
return true;
}
/**
* 数组模拟哈希法
*
* @param s
* @param t
* @return
*/
public boolean isAnagram_array(String s, String t) {
if (s.length() != t.length()) return false;
int[] arr = new int[26];
for (Character c : s.toCharArray()) {
arr[c-'a']++;
}
for (Character c : t.toCharArray()) {
arr[c-'a']--;
if (arr[c-'a'] < 0) return false;
}
return true;
}
@Test
public void test_isAnagram() {
Assert.assertFalse(isAnagram_hash("ab","a"));
Assert.assertTrue(isAnagram_hash("anagram","nagaram"));
Assert.assertTrue(isAnagram_array("anagram","nagaram"));
}
}