Formatted question description: https://leetcode.ca/all/1170.html
1170. Compare Strings by Frequency of the Smallest Character (Easy)
Let's define a function f(s)
over a non-empty string s
, which calculates the frequency of the smallest character in s
. For example, if s = "dcce"
then f(s) = 2
because the smallest character is "c"
and its frequency is 2.
Now, given string arrays queries
and words
, return an integer array answer
, where each answer[i]
is the number of words such that f(queries[i])
< f(W)
, where W
is a word in words
.
Example 1:
Input: queries = ["cbd"], words = ["zaaaz"] Output: [1] Explanation: On the first query we have f("cbd") = 1, f("zaaaz") = 3 so f("cbd") < f("zaaaz").
Example 2:
Input: queries = ["bbb","cc"], words = ["a","aa","aaa","aaaa"] Output: [1,2] Explanation: On the first query only f("bbb") < f("aaaa"). On the second query both f("aaa") and f("aaaa") are both > f("cc").
Constraints:
1 <= queries.length <= 2000
1 <= words.length <= 2000
1 <= queries[i].length, words[i].length <= 10
queries[i][j]
,words[i][j]
are English lowercase letters.
Solution 1.
// OJ: https://leetcode.com/problems/compare-strings-by-frequency-of-the-smallest-character/
// Time: O(W*Q)
// Space: O(W)
class Solution {
int frequency(string &s) {
int ch = 'z', cnt = 0;
for (char c : s) {
if (c < ch) {
cnt = 1;
ch = c;
} else if (c == ch) ++cnt;
}
return cnt;
}
public:
vector<int> numSmallerByFrequency(vector<string>& Q, vector<string>& W) {
vector<int> F(W.size()), ans;
for (int i = 0; i < W.size(); ++i) F[i] = frequency(W[i]);
for (auto &s : Q) {
int cnt = 0, f = frequency(s);
for (int i = 0; i < W.size(); ++i) cnt += F[i] > f;
ans.push_back(cnt);
}
return ans;
}
};
Solution 2.
// OJ: https://leetcode.com/problems/compare-strings-by-frequency-of-the-smallest-character/
// Time: O(W + Q)
// Space: O(1)
class Solution {
int frequency(string &s) {
int ch = 'z', cnt = 0;
for (char c : s) {
if (c < ch) {
cnt = 1;
ch = c;
} else if (c == ch) ++cnt;
}
return cnt;
}
public:
vector<int> numSmallerByFrequency(vector<string>& Q, vector<string>& W) {
vector<int> F(11), ans;
for (int i = 0; i < W.size(); ++i) F[frequency(W[i])]++;
for (int i = 1; i < 11; ++i) F[i] += F[i - 1];
for (auto &s : Q) ans.push_back(W.size() - F[frequency(s)]);
return ans;
}
};
Java
class Solution {
public int[] numSmallerByFrequency(String[] queries, String[] words) {
int queriesLength = queries.length, wordsLength = words.length;
int[] queriesFrequency = new int[queriesLength];
int[] wordsFrequency = new int[wordsLength];
for (int i = 0; i < queriesLength; i++)
queriesFrequency[i] = frequency(queries[i]);
for (int i = 0; i < wordsLength; i++)
wordsFrequency[i] = frequency(words[i]);
int[] nums = new int[queriesLength];
for (int i = 0; i < queriesLength; i++) {
int queryFrequency = queriesFrequency[i];
for (int j = 0; j < wordsLength; j++) {
int wordFrequency = wordsFrequency[j];
if (queryFrequency < wordFrequency)
nums[i]++;
}
}
return nums;
}
public int frequency(String str) {
int[] count = new int[26];
char[] array = str.toCharArray();
for (char c : array)
count[c - 'a']++;
for (int i = 0; i < 26; i++) {
if (count[i] != 0)
return count[i];
}
return 0;
}
}