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Amazon OA新题 用户-好友-好友推荐的课程 code

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laonong15 发表于 2016-2-24 04:53:48 | 显示全部楼层 |阅读模式

2016(1-3月) 码农类 本科 全职@Amazon - Other - 技术电面 |Other其他

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the original  link  is :
http://www.1point3acres.com/bbs/ ... p;page=1#pid2230193

just  write the code  by myself,  but  didnt test it :

package Amazoninterview;.鐣欏璁哄潧-涓浜-涓夊垎鍦

import java.util.Collections;
import java.util.Comparator;. from: 1point3acres.com/bbs
import java.util.HashMap;
import java.util.HashSet;
import java.util.Iterator;
import java.util.LinkedHashMap;
import java.util.LinkedList;
import java.util.List;
import java.util.Map;

/*
* 1. Use a HashSet<String> courseSet and store all the courses made by the user
2. Keep one more HashMap<Course, Integer> recommendation
2. Get the list of Friends for the user
3. Iterate through the friends list and in that find the courses selected by the friend
4. If the course present in courseSet, omit else, put it in recommendation and increment it's count by 1.
5. After all the friends are evaluated. Sort the recommendation by it's value,  

t's O(n) Space  because n is the number of courses selected in total by all your friends.
A  it would be O(k*p) where k is the number of friends and p is the number of courses a friend selects
*/. from: 1point3acres.com/bbs
public class Recommender {. 涓浜-涓夊垎-鍦帮紝鐙鍙戝竷

        public static void main(String[] args) {
               
        }. visit 1point3acres.com for more.
        public static Map<String,Integer> getRecommedations(String userId){
                List<String> friends = getFriendsListForUser(userId);
                HashSet<String> myCourses = getCoursesForUser( userId);
                if(friends ==null || friends.size() ==0 )
                        return null;
                if(myCourses == null). 鐗涗汉浜戦泦,涓浜╀笁鍒嗗湴
                        myCourses = new HashSet<String>();
                HashMap<String,Integer> recommendMap = new HashMap<String,Integer>();
                for(String friend:friends){
                        HashSet<String> friendCourseList = getCoursesForUser( friend);. From 1point 3acres bbs
                        for(String course:friendCourseList){. 1point 3acres 璁哄潧
                                if(myCourses.contains(course))
                                        continue;
                                if(recommendMap.get(course)!=null){-google 1point3acres
                                        recommendMap.put(course, recommendMap.get(course)+1);
                                }
                                else{
                                        recommendMap.put(course,1);
                                }
                        }
                }
                if(recommendMap !=null && recommendMap.size() >0)
                        return sortByValue(recommendMap);
                return null;
        }.鐣欏璁哄潧-涓浜-涓夊垎鍦
       
        public static Map sortByValue(Map unsortMap) {         
                List list = new LinkedList(unsortMap.entrySet());
         . 鐣欏鐢宠璁哄潧-涓浜╀笁鍒嗗湴
                Collections.sort(list, new Comparator() {
                        public int compare(Object o1, Object o2) {
                                return ((Comparable) ((Map.Entry) (o1)).getValue()) 鏉ユ簮涓浜.涓夊垎鍦拌鍧.
                                                        .compareTo(((Map.Entry) (o2)).getValue());.鐣欏璁哄潧-涓浜-涓夊垎鍦
                        }
                });
         
                Map sortedMap = new LinkedHashMap();-google 1point3acres
                for (Iterator it = list.iterator(); it.hasNext();) {
                        Map.Entry entry = (Map.Entry) it.next();
                        sortedMap.put(entry.getKey(), entry.getValue());
                }
                return sortedMap;
        }
       
        //giving function
       
        public static  List<String> getFriendsListForUser(String userId){
                return null;       
        }
        public static HashSet<String>getCoursesForUser(String userId){
                return null;
        }
}

hopfully  it helps. from: 1point3acres.com/bbs
. Waral 鍗氬鏈夋洿澶氭枃绔,

. 鐣欏鐢宠璁哄潧-涓浜╀笁鍒嗗湴
daykills 发表于 2016-2-24 09:43:23 | 显示全部楼层
我面的也是这题...你后来需要搞个半小时的电话面谈吗?
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