C# 代码
public class Solution {
public bool IsIsomorphic(string s, string t) {
Dictionary<char, char> map1 = new Dictionary<char, char>();
Dictionary<char, char> map2 = new Dictionary<char, char>();
for (int i = 0; i < s.Length; i++){
if ((map1.ContainsKey(s[i]) && map1[s[i]] != t[i]) || (map2.ContainsKey(t[i]) && map2[t[i]] != s[i])) return false;
map1.TryAdd(s[i], t[i]);
map2.TryAdd(t[i], s[i]);
}
return true;
}
}