leetcode 205. Isomorphic Strings(哈希表)

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.

题解：显然是哈希查找，但是其实没必要用map，一共就255个字符，每次只记录它现在的位置就好（因为之前的位置都比较过了）。

class Solution {
public:
    bool isIsomorphic(string s, string t) {
        int hs[256]={0};
        int ht[256]={0};
        int ls=s.length(),lt=t.length();
        if(ls!=lt) return false;
        for(int i=0;i<ls;i++){
            if(hs[s[i]]!=ht[t[i]]){
                return false;
            }
            hs[s[i]]=i+1;
            ht[t[i]]=i+1;
        }
        return true;
    }
};