LeetCode 205-Isomorphic Strings-优快云博客

本文链接：https://blog.youkuaiyun.com/keitho00/article/details/45366833

本文详细阐述了如何通过数字映射的方法，判断两个字符串是否具有同构性，即字符间的替换关系是否一致。通过将字符串转换为数字序列并比较，我们能有效地解决同构性检测的问题，此方法适用于编程基础的理解和应用。

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Given two strings s and t, determine if they are isomorphic.

Two strings are isomorphic if the characters in s can be replaced to get t.

All occurrences of a character must be replaced with another character while preserving the order of characters. No two characters may map to the same character but a character may map to itself.

For example,
Given "egg", "add", return true.

Given "foo", "bar", return false.

Given "paper", "title", return true.

题目解析：该题要看两组字符串是不是成对应关系，我的想法是将其变成数字组成的字符串，然后判断是否相等，该题没什么难点，关键在于字符串的拼接不要用String

代码：

public class Solution {
    public boolean isIsomorphic(String s, String t) {
	
	String s1=getNumber(s);
	String s2=getNumber(t);
	if(s1.equals(s2)){
		return true;
	}else{
		return false;
	}
        
    }

public static String getNumber(String st){
	Map<Character,Integer> map =new HashMap<Character,Integer>();
	char[] ch=st.toCharArray();
	StringBuilder re=new StringBuilder();
	for(int i=0,j=0;i<ch.length;i++){
		if(!map.containsKey(ch[i])){
			map.put(ch[i], j);
			j++;
			re=re.append(map.get(ch[i]));
		}else{
			re=re.append(map.get(ch[i]));
		}
	}
	return re.toString();
}
}