205. Isomorphic Strings

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.

题意：计算两个字符串是否同构。注意：你可以假设两个字符串的长度一致。

思路：将字符串转换为对应的数字组合，然后判断是否相同，如：egg->122, add->122同构；foo->122,bar->123,不同构。

class Solution {public:bool isIsomorphic(string s, string t) {if (s.empty() && t.empty())return true;int *s_num, *t_num;getIsomorphic(s, s_num);getIsomorphic(t, t_num);for (int i = 0; i < s.size(); i++){if (s_num[i] != t_num[i])return false;}return true;}int getIsomorphic(string s, int*& s_num){map<char, int> myMap;s_num = new int[s.size()];int val = 1;for (int i = 0; i < s.size(); i++){char ch = s[i];if (myMap.insert(pair<char, int>(ch, val)).second){s_num[i] = val;val++;}else{s_num[i] = myMap[ch];}}return 0;}};