LeetCode 205 - Isomorphic Strings

一、问题描述

Description：

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

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.

Note：

You may assume both s and t have the same length.

二、解题报告

所谓的“同构”，就是字符串 s 中的字符可以一对一的映射到字符串 t 中的字符。不能一对多，也不能多对一。

这里，我的解法是维护两个 map，判断是否是一对一的映射关系：

// s 和 t 具有相同的长度
bool isIsomorphic(string s, string t) {
map<char, char> m1;
map<char, char> m2;
bool flag = true;
for(int i=0; i<s.size(); ++i)
{
if(m1.find(s[i])==m1.end() && m2.find(t[i])==m2.end())
{
m1[s[i]] = t[i];
m2[t[i]] = s[i];
}
else if(m1.find(s[i])!=m1.end() && m2.find(t[i])!=m2.end())
{
if(m1[s[i]]!=t[i] || m2[t[i]]!=s[i])
{
flag = false;
break;
}
}
else
{
flag = false;
break;
}
}
return flag;
}

LeetCode答案源代码：https://github.com/SongLee24/LeetCode