Today I have done Water Bottles and leetcode's March LeetCoding Challenge with cpp.

Water Bottles

Description

Given numBottles full water bottles, you can exchange numExchange empty water bottles for one full water bottle.

The operation of drinking a full water bottle turns it into an empty bottle.

Return the maximum number of water bottles you can drink.

Example 1:

Input: numBottles = 9, numExchange = 3
Output: 13
Explanation: You can exchange 3 empty bottles to get 1 full water bottle.
Number of water bottles you can drink: 9 + 3 + 1 = 13.

Example 2:

Input: numBottles = 15, numExchange = 4
Output: 19
Explanation: You can exchange 4 empty bottles to get 1 full water bottle. 
Number of water bottles you can drink: 15 + 3 + 1 = 19.

Example 3:

Input: numBottles = 5, numExchange = 5
Output: 6

Example 4:

Input: numBottles = 2, numExchange = 3
Output: 2

Constraints:

• 1 <= numBottles <= 100
• 2 <= numExchange <= 100

Solution

class Solution {
public:
  int numWaterBottles(int numBottles, int numExchange) {
    int bottle = 0;
    int drink = 0;
    while(numBottles) {
      drink += numBottles;
      bottle = bottle + numBottles;
      numBottles = bottle / numExchange;
      bottle = bottle % numExchange;
    }
    return drink;
  }
};

March LeetCoding Challenge 22

Description

Vowel Spellchecker

Given a wordlist, we want to implement a spellchecker that converts a query word into a correct word.

For a given query word, the spell checker handles two categories of spelling mistakes:

• Capitalization: If the query matches a word in the wordlist (

  case-insensitive

  ), then the query word is returned with the same case as the case in the wordlist.

  • Example: wordlist = ["yellow"], query = "YellOw": correct = "yellow"
  • Example: wordlist = ["Yellow"], query = "yellow": correct = "Yellow"
  • Example: wordlist = ["yellow"], query = "yellow": correct = "yellow"

• Vowel Errors: If after replacing the vowels ('a', 'e', 'i', 'o', 'u') of the query word with any vowel individually, it matches a word in the wordlist (

  case-insensitive

  ), then the query word is returned with the same case as the match in the wordlist.

  • Example: wordlist = ["YellOw"], query = "yollow": correct = "YellOw"
  • Example: wordlist = ["YellOw"], query = "yeellow": correct = "" (no match)
  • Example: wordlist = ["YellOw"], query = "yllw": correct = "" (no match)

In addition, the spell checker operates under the following precedence rules:

• When the query exactly matches a word in the wordlist (case-sensitive), you should return the same word back.
• When the query matches a word up to capitlization, you should return the first such match in the wordlist.
• When the query matches a word up to vowel errors, you should return the first such match in the wordlist.
• If the query has no matches in the wordlist, you should return the empty string.

Given some queries, return a list of words answer, where answer[i] is the correct word for query = queries[i].

Example 1:

Input: wordlist = ["KiTe","kite","hare","Hare"], queries = ["kite","Kite","KiTe","Hare","HARE","Hear","hear","keti","keet","keto"]
Output: ["kite","KiTe","KiTe","Hare","hare","","","KiTe","","KiTe"]

Note:

• 1 <= wordlist.length <= 5000
• 1 <= queries.length <= 5000
• 1 <= wordlist[i].length <= 7
• 1 <= queries[i].length <= 7
• All strings in wordlist and queries consist only of english letters.

Solution

class Solution {
  string stringTolower(string word) {
    for(auto &c : word) c = tolower(c);
    return word;
  }
  
  string vowelUnify(string word) {
    word = stringTolower(word);
    for(auto &c : word) {
      switch (c) {
        case 'a':
        case 'e':
        case 'i':
        case 'o':
        case 'u':
          c = '?';
      }
    }
    return word;
  }
public:
  vector<string> spellchecker(vector<string>& wordlist, vector<string>& queries) {
    unordered_set<string> words(wordlist.begin(), wordlist.end());
    unordered_map<string, string> capitError;
    unordered_map<string, string> vowelError;
    for(auto word : wordlist) {
      string vowel = vowelUnify(word);
      if(!vowelError.count(vowel)) vowelError[vowel] = word;
      string lower = stringTolower(word);
      if(!capitError.count(lower)) capitError[lower] = word;
    }
    
    vector<string> answer;
    for(auto query : queries) {
      if(words.count(query)) {
        answer.push_back(query);
        continue;
      }
      string lower = stringTolower(query);
      if(capitError.count(lower)) {
        answer.push_back(capitError[lower]);
        continue;
      }
      string vowel = vowelUnify(query);
      if(vowelError.count(vowel)) {
        answer.push_back(vowelError[vowel]);
        continue;
      }
      answer.push_back("");
    }
    
    return answer;
  }
};