LeetCode - 692. Top K Frequent Words
Problem Statement
Given a non-empty list of words, return the k most frequent elements.
Your answer should be sorted by frequency from highest to lowest. If two words have the same frequency, then the word with the lower alphabetical order comes first.
Example: 1
Input: ["i", "love", "leetcode", "i", "love", "coding"], k = 2
Output: ["i", "love"]
Explanation: "i" and "love" are the two most frequent words.
Note that "i" comes before "love" due to a lower alphabetical order.
Example: 2
Input: ["the", "day", "is", "sunny", "the", "the", "the", "sunny", "is", "is"], k = 4
Output: ["the", "is", "sunny", "day"]
Explanation: "the", "is", "sunny" and "day" are the four most frequent words,
with the number of occurrence being 4, 3, 2 and 1 respectively.
Solution
import "sort"
type entry struct {
word string
frequence int
}
type freWords []*entry
func topKFrequent(words []string, k int) []string {
count := make(map[string]int, len(words))
for _, w := range words {
count[w]++
}
fw := make(freWords, 0, len(count))
for w, c := range count {
fw = append(fw, &entry{
word: w,
frequence: c,
})
}
sort.Slice(fw, func(i, j int) bool {
if fw[i].frequence == fw[j].frequence {
return fw[i].word < fw[j].word
}
return fw[i].frequence > fw[j].frequence
})
res := make([]string, k)
for i := 0; i < k; i++ {
res[i] = fw[i].word
}
return res
}