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Formatted question description: https://leetcode.ca/all/916.html

916. Word Subsets (Medium)

We are given two arrays A and B of words.  Each word is a string of lowercase letters.

Now, say that word b is a subset of word a if every letter in b occurs in a, including multiplicity.  For example, "wrr" is a subset of "warrior", but is not a subset of "world".

Now say a word a from A is universal if for every b in B, b is a subset of a. 

Return a list of all universal words in A.  You can return the words in any order.

 

Example 1:

Input: A = ["amazon","apple","facebook","google","leetcode"], B = ["e","o"]
Output: ["facebook","google","leetcode"]

Example 2:

Input: A = ["amazon","apple","facebook","google","leetcode"], B = ["l","e"]
Output: ["apple","google","leetcode"]

Example 3:

Input: A = ["amazon","apple","facebook","google","leetcode"], B = ["e","oo"]
Output: ["facebook","google"]

Example 4:

Input: A = ["amazon","apple","facebook","google","leetcode"], B = ["lo","eo"]
Output: ["google","leetcode"]

Example 5:

Input: A = ["amazon","apple","facebook","google","leetcode"], B = ["ec","oc","ceo"]
Output: ["facebook","leetcode"]

 

Note:

  1. 1 <= A.length, B.length <= 10000
  2. 1 <= A[i].length, B[i].length <= 10
  3. A[i] and B[i] consist only of lowercase letters.
  4. All words in A[i] are unique: there isn't i != j with A[i] == A[j].

Related Topics:
String

Solution 1.

  • class Solution {
    public List<String> wordSubsets(String[] A, String[] B) {
        List<String> universalList = new ArrayList<String>();
        int[] counts = getMaxCounts(B);
        for (String word : A) {
            int[] wordCounts = getWordCounts(word);
            boolean flag = true;
            for (int i = 0; i < 26; i++) {
                if (wordCounts[i] < counts[i]) {
                    flag = false;
                    break;
                }
            }
            if (flag)
                universalList.add(word);
        }
        return universalList;
    }

    public int[] getMaxCounts(String[] array) {
        int[] counts = new int[26];
        for (String word : array) {
            int[] curCounts = new int[26];
            char[] wordArray = word.toCharArray();
            for (char c : wordArray)
                curCounts[c - 'a']++;
            for (int i = 0; i < 26; i++)
                counts[i] = Math.max(counts[i], curCounts[i]);
        }
        return counts;
    }

    public int[] getWordCounts(String word) {
        int[] wordCounts = new int[26];
        char[] wordArray = word.toCharArray();
        for (char c : wordArray)
            wordCounts[c - 'a']++;
        return wordCounts;
    }
}

############

class Solution {
    public List<String> wordSubsets(String[] words1, String[] words2) {
        int[] cnt = new int[26];
        for (var b : words2) {
            int[] t = new int[26];
            for (int i = 0; i < b.length(); ++i) {
                t[b.charAt(i) - 'a']++;
            }
            for (int i = 0; i < 26; ++i) {
                cnt[i] = Math.max(cnt[i], t[i]);
            }
        }
        List<String> ans = new ArrayList<>();
        for (var a : words1) {
            int[] t = new int[26];
            for (int i = 0; i < a.length(); ++i) {
                t[a.charAt(i) - 'a']++;
            }
            boolean ok = true;
            for (int i = 0; i < 26; ++i) {
                if (cnt[i] > t[i]) {
                    ok = false;
                    break;
                }
            }
            if (ok) {
                ans.add(a);
            }
        }
        return ans;
    }
}

  • // OJ: https://leetcode.com/problems/word-subsets/
// Time: O((A + B) * N) where N is the maximum length of string
// Space: O(1)
class Solution {
public:
    vector<string> wordSubsets(vector<string>& A, vector<string>& B) {
        int N = A.size(), target[26] = {}, j = 0;
        for (auto &b : B) {
            int cnt[26] = {};
            for (char c : b) cnt[c - 'a']++;
            for (int i = 0; i < 26; ++i) target[i] = max(target[i], cnt[i]);
        }
        for (int i = 0; i < N; ++i) {
            int cnt[26] = {};
            for (char c : A[i]) cnt[c - 'a']++;
            bool valid = true;
            for (int k = 0; k < 26 && valid; ++k) valid = target[k] <= cnt[k];
            if (valid) A[j++] = A[i];
        }
        A.resize(j);
        return A;
    }
};

  • class Solution:
    def wordSubsets(self, words1: List[str], words2: List[str]) -> List[str]:
        cnt = Counter()
        for b in words2:
            t = Counter(b)
            for c, v in t.items():
                cnt[c] = max(cnt[c], v)
        ans = []
        for a in words1:
            t = Counter(a)
            if all(v <= t[c] for c, v in cnt.items()):
                ans.append(a)
        return ans

############

class Solution(object):
    def wordSubsets(self, A, B):
        """
        :type A: List[str]
        :type B: List[str]
        :rtype: List[str]
        """
        B = set(B)
        res = []
        count = collections.defaultdict(int)
        for b in B:
            cb = collections.Counter(b)
            for c, v in cb.items():
                count[c] = max(count[c], v)
        res = []
        for a in A:
            ca = collections.Counter(a)
            isSuccess = True
            for c, v in count.items():
                if v > ca[c]:
                    isSuccess = False
                    break
            if isSuccess:
                res.append(a)
        return res

  • func wordSubsets(words1 []string, words2 []string) (ans []string) {
	cnt := [26]int{}
	for _, b := range words2 {
		t := [26]int{}
		for _, c := range b {
			t[c-'a']++
		}
		for i := range cnt {
			cnt[i] = max(cnt[i], t[i])
		}
	}
	for _, a := range words1 {
		t := [26]int{}
		for _, c := range a {
			t[c-'a']++
		}
		ok := true
		for i, v := range cnt {
			if v > t[i] {
				ok = false
				break
			}
		}
		if ok {
			ans = append(ans, a)
		}
	}
	return
}

func max(a, b int) int {
	if a > b {
		return a
	}
	return b
}

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