leetCode 205. Isomorphic Strings 哈希 字符串相似

205. Isomorphic Strings 字符串相似

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.

題目大意：

判斷兩個(gè)字符串是否相似。

思路：

使用雙map來進(jìn)行比較。map鍵為字符串元素，值為字符上一次出現(xiàn)的位置。

代碼如下：

class Solution {
public:
    bool isIsomorphic(string s, string t) {
        if(s.size() != t.size())
            return false;
        unordered_map<char,int> maps;
        unordered_map<char,int> mapt;
        for(int i = 0;i < s.size();i++)
        {
            if(maps.find(s[i]) == maps.end() && mapt.find(t[i]) == mapt.end())
            {
                maps.insert(pair<char,int>(s[i],i));
                mapt.insert(pair<char,int>(t[i],i));
            }
            else if(maps.find(s[i]) != maps.end() && mapt.find(t[i]) != mapt.end())
            {
                if(maps[s[i]] != mapt[t[i]])
                    return false;
                else
                {
                    maps[s[i]] = i;
                    mapt[t[i]] = i;
                }
            }
            else
                return false;
        }
        return true;
    }
};

2016-08-13 17:15:21