---
tags: leetcode
---

# [2135. Count Words Obtained After Adding a Letter](https://leetcode.com/problems/count-words-obtained-after-adding-a-letter/)
---
# My Solution
## The Key Idea for Solving This Coding Question
## C++ Code

class Solution {
public:
    int wordCount(vector<string> &startWords, vector<string> &targetWords) {
        unordered_set<unsigned int> hashedStartWords;
        for (auto &startWord : startWords) {
            hashedStartWords.insert(hashString(startWord));
        }

        int machedCnt = 0;
        for (auto &targetWord : targetWords) {
            for (int skip = 0; skip < targetWord.size(); ++skip) {
                unsigned int hashedTargetWord = hashString2(targetWord, skip);
                if (hashedStartWords.find(hashedTargetWord) != hashedStartWords.end()) {
                    ++machedCnt;
                    break;
                }
            }
        }
        return machedCnt;
    }

private:
    unsigned int hashString(string &s) {
        unsigned int hash = 0;
        for (auto &c : s) {
            hash = hash + (1 << (c - 'a'));
        }

        return hash;
    }

    unsigned int hashString2(string &s, int skip) {
        unsigned int hash = 0;
        for (int i = 0; i < s.size(); ++i) {
            if (i == skip) {
                continue;
            }
            hash = hash + (1 << (s[i] - 'a')); 
        }
        return hash;
    }
};

## Time Complexity
## Space Complexity
# Miscellane
<!--
# Test Cases

["ant","act","tack"]
["tack","act","acti"]

["ab","a"]
["abc","abcd"]

* Wrong Answer

["g","vf","ylpuk","nyf","gdj","j","fyqzg","sizec"]
["r","am","jg","umhjo","fov","lujy","b","uz","y"]

* Time Limit Exceeded
https://leetcode.com/problems/count-words-obtained-after-adding-a-letter/submissions/839285643/
* Time Limit Exceeded
https://leetcode.com/problems/count-words-obtained-after-adding-a-letter/submissions/847342898/
-->