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LC 890. Find and Replace Pattern

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You have a list of words and a pattern, and you want to know which words in words matches the pattern.

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.

)

Return a list of the words in words that match the given pattern.

You may return the answer in any order.

Example 1:

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.

Note:

  • 1 <= words.length <= 50
  • 1 <= pattern.length = words[i].length <= 20

Runtime: 4 ms, faster than 62.45% of C++ online submissions for Find and Replace Pattern.

註意一一對應要用兩個字典。

class Solution {
public:
  vector<string> findAndReplacePattern(vector<string>& words, string
pattern) { vector<string> ret; for(auto word : words){ if(word.size() != pattern.size()) continue; unordered_map<char,char> mp_w2p; unordered_map<char,char> mp_p2w; bool shouldput = true; for(int i=0; i<word.size(); i++){ if(!mp_w2p.count(word[i]) && !mp_p2w.count(pattern[i])){ mp_w2p[word[i]] = pattern[i]; mp_p2w[pattern[i]] = word[i]; } else if(!mp_w2p.count(word[i]) || !mp_p2w.count(pattern[i])) { shouldput = false; break; }else if(mp_w2p[word[i]] != pattern[i] || mp_p2w[pattern[i]] != word[i]){ shouldput = false; break; } } if(shouldput) ret.push_back(word); } return ret; } };

LC 890. Find and Replace Pattern