Question

809. Expressive Words

中文文档

Description

Sometimes people repeat letters to represent extra feeling. For example:

• "hello" -> "heeellooo"
• "hi" -> "hiiii"

In these strings like "heeellooo", we have groups of adjacent letters that are all the same: "h", "eee", "ll", "ooo".

You are given a string s and an array of query strings words. A query word is stretchy if it can be made to be equal to s by any number of applications of the following extension operation: choose a group consisting of characters c, and add some number of characters c to the group so that the size of the group is three or more.

• For example, starting with "hello", we could do an extension on the group "o" to get "hellooo", but we cannot get "helloo" since the group "oo" has a size less than three. Also, we could do another extension like "ll" -> "lllll" to get "helllllooo". If s = "helllllooo", then the query word "hello" would be stretchy because of these two extension operations: query = "hello" -> "hellooo" -> "helllllooo" = s.

Return _the number of query strings that are stretchy_.

 

Example 1:

Input: s = "heeellooo", words = ["hello", "hi", "helo"]
Output: 1
Explanation: 
We can extend "e" and "o" in the word "hello" to get "heeellooo".
We can't extend "helo" to get "heeellooo" because the group "ll" is not size 3 or more.

Example 2:

Input: s = "zzzzzyyyyy", words = ["zzyy","zy","zyy"]
Output: 3

 

Constraints:

• 1 <= s.length, words.length <= 100
• 1 <= words[i].length <= 100
• s and words[i] consist of lowercase letters.

Solutions

Solution 1

class Solution:
  def expressiveWords(self, s: str, words: List[str]) -> int:
    def check(s, t):
      m, n = len(s), len(t)
      if n > m:
        return False
      i = j = 0
      while i < m and j < n:
        if s[i] != t[j]:
          return False
        k = i
        while k < m and s[k] == s[i]:
          k += 1
        c1 = k - i
        i, k = k, j
        while k < n and t[k] == t[j]:
          k += 1
        c2 = k - j
        j = k
        if c1 < c2 or (c1 < 3 and c1 != c2):
          return False
      return i == m and j == n

    return sum(check(s, t) for t in words)

class Solution {
  public int expressiveWords(String s, String[] words) {
    int ans = 0;
    for (String t : words) {
      if (check(s, t)) {
        ++ans;
      }
    }
    return ans;
  }

  private boolean check(String s, String t) {
    int m = s.length(), n = t.length();
    if (n > m) {
      return false;
    }
    int i = 0, j = 0;
    while (i < m && j < n) {
      if (s.charAt(i) != t.charAt(j)) {
        return false;
      }
      int k = i;
      while (k < m && s.charAt(k) == s.charAt(i)) {
        ++k;
      }
      int c1 = k - i;
      i = k;
      k = j;
      while (k < n && t.charAt(k) == t.charAt(j)) {
        ++k;
      }
      int c2 = k - j;
      j = k;
      if (c1 < c2 || (c1 < 3 && c1 != c2)) {
        return false;
      }
    }
    return i == m && j == n;
  }
}

class Solution {
public:
  int expressiveWords(string s, vector<string>& words) {
    auto check = [](string& s, string& t) -> int {
      int m = s.size(), n = t.size();
      if (n > m) return 0;
      int i = 0, j = 0;
      while (i < m && j < n) {
        if (s[i] != t[j]) return 0;
        int k = i;
        while (k < m && s[k] == s[i]) ++k;
        int c1 = k - i;
        i = k, k = j;
        while (k < n && t[k] == t[j]) ++k;
        int c2 = k - j;
        j = k;
        if (c1 < c2 || (c1 < 3 && c1 != c2)) return 0;
      }
      return i == m && j == n;
    };

    int ans = 0;
    for (string& t : words) ans += check(s, t);
    return ans;
  }
};

func expressiveWords(s string, words []string) (ans int) {
  check := func(s, t string) bool {
    m, n := len(s), len(t)
    if n > m {
      return false
    }
    i, j := 0, 0
    for i < m && j < n {
      if s[i] != t[j] {
        return false
      }
      k := i
      for k < m && s[k] == s[i] {
        k++
      }
      c1 := k - i
      i, k = k, j
      for k < n && t[k] == t[j] {
        k++
      }
      c2 := k - j
      j = k
      if c1 < c2 || (c1 != c2 && c1 < 3) {
        return false
      }
    }
    return i == m && j == n
  }
  for _, t := range words {
    if check(s, t) {
      ans++
    }
  }
  return ans
}