Amazon10月10日网上笔试题1
题目简述：找到买一件物品的用户买的最多的另外一件物品。
例子：cus1 item1 cus2 item2 cus3 item3 cus2 item1 cus3 item4 cus1 item2 cus1 item4
当输入item1，则输出item2，因为有cus1和cus2买了item1，所以检查cus1和cus2一共买了什么，除了item1外有item2 和item4，item2数量为2，item4为1，所以输出为item2
具体代码如下：（当时写的代码，未优化）
import java.util.Scanner;import java.util.StringTokenizer;import java.util.HashMap;import java.util.Map.Entry;public class Solution {private String findMostlyBroughtItem(String[] shoppingRecordArray, String itemX) {// your code is hereHashMap<String,Integer> map = new HashMap<String,Integer>();HashMap<String,String> map1 = new HashMap<String,String>();int len = shoppingRecordArray.length;for(int i=0;i<len;i++){if(i%2==0){if(shoppingRecordArray[i+1].equals(itemX)){map1.put(shoppingRecordArray[i],"");}}}for(int i=0;i<len;i++){if(i%2==0){for(Entry<String, String> e: map1.entrySet()){if(shoppingRecordArray[i].equals(e.getKey())){if(shoppingRecordArray[i+1].equals(itemX)!=true){if(map.containsKey(shoppingRecordArray[i+1])){map.put(shoppingRecordArray[i+1],map.get(shoppingRecordArray[i+1])+1);}else{map.put(shoppingRecordArray[i+1], 1);}}}}}}int max = 0;String temp = "";for(Entry<String, Integer> e: map.entrySet()){if(e.getValue()>max){max = e.getValue();temp = e.getKey();}}if(map.isEmpty()){return "None";}else{return temp;} }public static void main(String[] args) {Solution solution = new Solution();Scanner scanner = new Scanner(System.in);while (scanner.hasNextLine()) {//Initialize the item XString itemX = scanner.nextLine();//Initialize the shopping record arrayString strLine2 = scanner.nextLine();StringTokenizer stringTokenizer = new StringTokenizer(strLine2);int arrayLength = stringTokenizer.countTokens();String[] shoppingRecordArray = new String[arrayLength];for(int j = 0; j < arrayLength; j++){shoppingRecordArray[j] = stringTokenizer.nextToken();}String mostlyBroughtItem = solution.findMostlyBroughtItem(shoppingRecordArray, itemX);System.out.println(mostlyBroughtItem);}}}