LeetCode:Isomorphic Strings
problem:
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.
solution:这道题木实则判断两个字符串是否为同构字符串。只要保证s t 互相都映射成功,用unordered_map 来记录它们之间的相互映射
class Solution { public: bool isIsomorphic(string s, string t) { if(s.size()!=t.size()) return false; unordered_map<char,char> datamap; for(int i=0;i<s.size();i++) { if(datamap.find(s[i])==datamap.end()) datamap[s[i]]=t[i]; else if(datamap[s[i]]!=t[i]) return false; } datamap.clear();
for(int i=0;i<t.size();i++) { if(datamap.find(t[i])==datamap.end()) datamap[t[i]]=s[i]; else if(datamap[t[i]]!=s[i]) return false; } } };