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.
Note:
You may assume both s and t have the same length.
解题思路
建立两个表：
①从字符串s到字符串t的字符映照表，由于最大的字母为122，因此映照表的大小为123。映照表键值为s中的字符，value为t中对应位置的字符。
②isUsed表代表t中的该字符是不是已被作为s中某字符的value值。
实现代码
#include <iostream>
using namespace std;
//Runtime:12ms
class Solution {
public:
bool isIsomorphic(string s,string t) {
int len = s.size();
unsigned char map[123] = {0};
bool isUsed[123] = {0};
for (int i = 0; i < s.size(); i++)
{
if (map[s[i]] == 0)
{
if (!isUsed[t[i]])
{
map[s[i]] = t[i];
isUsed[t[i]] = true;
}
else
{
return false;
}
}
else if (map[s[i]] != t[i])
{
return false;
}
}
return true;
}
};
int main()
{
Solution s;
cout<<s.isIsomorphic("aba","baa")<<endl;
cout<<s.isIsomorphic("egg","add")<<endl;
cout<<s.isIsomorphic("foo","bar")<<endl;
cout<<s.isIsomorphic("paper","title")<<endl;
}