[LeetCode] Isomorphic Strings，leetcodeisomorphic

[LeetCode] Isomorphic Strings，leetcodeisomorphic

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.

解題思路

建立兩個表：
①從字串s到字串t的字元對應表，因為最大的字母為122，因此映射表的大小為123。映射表索引值為s中的字元，value為t中對應位置的字元。
②isUsed表代表t中的該字元是否已經被作為s中某字元的value值。

實現代碼

#include <iostream>using namespace std;//Runtime:12msclass 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;}