Isomorphic Strings.cpp

//Approach-1
class Solution {
public:
    bool isIsomorphic(string s, string t) {
        vector<int> mp1(256, -1);
        vector<int> mp2(256, -1);
        int n = s.length();
        
        for(int i = 0; i<n; i++) {
            char ch1 = s[i];
            char ch2 = t[i];
            
            if((mp1[ch1] != -1 && mp1[ch1] != ch2) ||
               (mp2[ch2] != -1  && mp2[ch2] != ch1)
               )
                return false;
            
            mp1[ch1] = ch2;
            mp2[ch2] = ch1;
            
        }
        
        return true;
    }
};


//Approach-2 (simplified)
class Solution {
public:
    bool isIsomorphic(string s, string t) {
        vector<int> mp1(256, -1);
        vector<int> mp2(256, -1);
        int n = s.length();
        
        for(int i = 0; i<n; i++) {
            char ch1 = s[i];
            char ch2 = t[i];
            
            if(mp1[ch1] != mp2[ch2])
                return false;
            
            mp1[ch1] = i;
            mp2[ch2] = i;
            
        }
        
        return true;
    }
};