1772-SortFeaturesByPopularity.go

package main

// 1772. Sort Features by Popularity
// You are given a string array features where features[i] is a single word that represents the name of a feature of the latest product you are working on. 
// You have made a survey where users have reported which features they like. 
// You are given a string array responses, where each responses[i] is a string containing space-separated words.

// The popularity of a feature is the number of responses[i] that contain the feature. 
// You want to sort the features in non-increasing order by their popularity. 
// If two features have the same popularity, order them by their original index in features. 
// Notice that one response could contain the same feature multiple times; 
// this feature is only counted once in its popularity.

// Return the features in sorted order.

// Example 1:
// Input: features = ["cooler","lock","touch"], responses = ["i like cooler cooler","lock touch cool","locker like touch"]
// Output: ["touch","cooler","lock"]
// Explanation: appearances("cooler") = 1, appearances("lock") = 1, appearances("touch") = 2. Since "cooler" and "lock" both had 1 appearance, "cooler" comes first because "cooler" came first in the features array.

// Example 2:
// Input: features = ["a","aa","b","c"], responses = ["a","a aa","a a a a a","b a"]
// Output: ["a","aa","b","c"]

// Constraints:
//     1 <= features.length <= 10^4
//     1 <= features[i].length <= 10
//     features contains no duplicates.
//     features[i] consists of lowercase letters.
//     1 <= responses.length <= 10^2
//     1 <= responses[i].length <= 10^3
//     responses[i] consists of lowercase letters and spaces.
//     responses[i] contains no two consecutive spaces.
//     responses[i] has no leading or trailing spaces.

import "fmt"
import "sort"
import "strings"

func sortFeatures(features []string, responses []string) []string {
    mp := make(map[string]int)
    for _, response := range responses {
        visited := map[string]bool{}
        strs := strings.Split(response, " ")
        for _, str := range strs {
            if visited[str] { continue } // 处理出现多次的情况, 不重复记录
            visited[str]=true
            mp[str]++
        }
    }
    sort.SliceStable(features, func(i, j int) bool { // 按出现的次数由高到低
        return mp[features[i]] > mp[features[j]]
    })
    return features
}

func main() {
    // Example 1:
    // Input: features = ["cooler","lock","touch"], responses = ["i like cooler cooler","lock touch cool","locker like touch"]
    // Output: ["touch","cooler","lock"]
    // Explanation: appearances("cooler") = 1, appearances("lock") = 1, appearances("touch") = 2. Since "cooler" and "lock" both had 1 appearance, "cooler" comes first because "cooler" came first in the features array.
    fmt.Println(sortFeatures([]string{"cooler","lock","touch"}, []string{"i like cooler cooler","lock touch cool","locker like touch"})) // ["touch","cooler","lock"]
    // Example 2:
    // Input: features = ["a","aa","b","c"], responses = ["a","a aa","a a a a a","b a"]
    // Output: ["a","aa","b","c"]
    fmt.Println(sortFeatures([]string{"a","aa","b","c"}, []string{"a","a aa","a a a a a","b a"})) // ["touch","cooler","lock"]
}