Hashing1 Complete

groupAna.cpp

@@ -0,0 +1,30 @@
+//we will assign prime no to each letters form a-z and then we will calculate the 
+//multiplication of each no if the multi is same then the string is an anargam and
+//will move to that map else we will create new mapping for that index
+//TC:0(nK) SC:O(n)
+class Solution {
+private:
+     double getHash(string&word){
+         double hash = 1;
+         int primes[26] = {2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101
+};
+     for(auto&it:word){
+       int key = it-'a';
+           hash = hash*primes[key];
+     }
+     return hash;
+     }
+public:
+    vector<vector<string>> groupAnagrams(vector<string>& strs) {
+        vector<vector<string>>ans;
+        unordered_map<double,vector<string>>mpp;
+        for(auto&qt:strs){
+           double g = getHash(qt);
+            mpp[g].push_back(qt);
+        }
+        for(auto&ct:mpp){
+            ans.push_back(ct.second);
+        }
+        return ans;
+    }
+};

isoStrings.cpp

@@ -0,0 +1,29 @@
+//use two maps to store mapping from both side
+//Iterate tbrough string if maping is correct return true else false
+//TC: O(n) SC O(n) 
+class Solution {
+public:
+    bool isIsomorphic(string s, string t) {
+        unordered_map<char,char>smap;
+        unordered_map<char,char>tmap;
+        for(int i =0;i<s.size();i++){
+            char sVal = s[i];
+            char tVal = t[i];
+            if(smap[sVal]){
+                // e g g
+                // a d d
+                if(smap[sVal]!=tVal)return false;
+            }
+            else {smap[sVal] = tVal;}
+        }
+        for(int i =0;i<s.size();i++){
+            char sVal = s[i];
+            char tVal = t[i];
+            if(tmap[tVal]){
+                if(tmap[tVal]!=sVal)return false;
+            }
+            else {tmap[tVal] = sVal;}
+        }
+        return true;
+    }
+};

wordPattern.cpp

@@ -0,0 +1,42 @@
+//TC:O(m+n)
+//SC:O(m+n)
+class Solution {
+private: 
+    string getWord(string&s,int& j){
+        string word;
+        while(j<s.size()&&s[j]!=' '){
+            word+=s[j];
+            j++;            
+        }
+        j++;
+        return word;
+
+    }
+public:
+    bool wordPattern(string pattern, string s) {
+        //declare two maps patteren to s & s to pattern
+        unordered_map<char,string>pts;
+        unordered_map<string,char>stp;
+        int j =0;
+        for(char c: pattern){
+            if(j>=s.size())return false;
+
+            string word = getWord(s,j);
+            //check if pattern is already in the map
+            auto it =pts.find(c);
+            //if it is already in the map and it is not mapped
+            // with the correctword return false
+            if(it!=pts.end() && it->second!=word){
+                return false;
+            }
+            //checking the second map that if it is also mapped with the same ele
+            auto qt = stp.find(word);
+            if(qt!=stp.end() && qt->second!=c) return false;
+            //
+            pts[c] = word;
+            stp[word] = c;
+        }
+        if(j>=s.size())return true;
+        return false;
+    }
+};