Added Find and Replace Pattern

Leetcode Question (Medium) related to string manipulation

Author: Anupam-Panwar

Strings/findAndReplacePattern.cpp

@@ -0,0 +1,69 @@
+/*
+Problem Statement
+
+Given a list of strings words and a string pattern, return a list of words[i] that match pattern. You may return the answer in any order.
+
+A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get the desired word.
+
+Recall that a permutation of letters is a bijection from letters to letters: every letter maps to another letter, and no two letters map to the same letter. 
+
+Input: words = ["abc","deq","mee","aqq","dkd","ccc"], pattern = "abb"
+Output: ["mee","aqq"]
+Explanation: "mee" matches the pattern because there is a permutation {a -> m, b -> e, ...}. 
+"ccc" does not match the pattern because {a -> c, b -> c, ...} is not a permutation, since a and b map to the same letter.
+
+Constraints:
+1 <= pattern.length <= 20
+1 <= words.length <= 50
+words[i].length == pattern.length
+pattern and words[i] are lowercase English letters.
+
+*/
+
+/*
+Time Complexity: O(N∗K), where N is the number of words, and K is the length of each word.
+Space Complexity: O(N∗K), the space used by the answer.
+*/
+
+#include<bits/stdc++.h>
+using namespace std;
+
+vector<string> findAndReplacePattern(vector<string> &words, string pattern)
+{
+    vector<string> ans;
+    for (int i = 0; i < words.size(); i++)
+    {
+        bool flag = true;
+        unordered_map<char, char> wordToPattern;
+        unordered_map<char, char> patternToWord;
+        for (int j = 0; j < pattern.length(); j++)
+        {
+            char wc = words[i][j];
+            char pc = pattern[j];
+            if (wordToPattern.count(wc) < 1)
+                wordToPattern[wc] = pc;
+            if (patternToWord.count(pc) < 1)
+                patternToWord[pc] = wc;
+
+            if (patternToWord[pc] != wc || wordToPattern[wc] != pc)
+            {
+                flag = false;
+                break;
+            }
+        }
+        if (flag == true)
+            ans.push_back(words[i]);
+    }
+    return ans;
+}
+
+int main()
+{
+    vector<string> words={"abc","deq","mee","aqq","dkd","ccc"};
+    string pattern="abb";
+    vector<string> ans=findAndReplacePattern(words,pattern);
+    for(string str:ans)
+    cout<<str<<" ";
+    return 0;
+}
+