【原創】查找字符的出現次數(一)

時間 2019-11-20

原文原文鏈接

（一）是我本身思考的java

（二）是同窗找到的正確的代碼面試

二者思路一致，在代碼功底上就體現出來孰優孰劣了，哈哈哈...算法

--------------------------------------------------------------------------------------------------------------------------數組

同窗在羣裏發了一到筆試題：dom

一個int數組裏面有100個隨機數，這些數中有重複的，請找出這100個數中每一個不重複的數的出現次數。測試

恩，大概就是這麼個意思。。大數據

當時想了想，得出個List<Map<String,int>>這麼個解決方法，思想就是從數組第一個元素開始遍歷，而後將結果放到Map裏面優化

具體操做就是：spa

數據：int[100]={1,2,2,1,2,132,1321,1,23,2,1,2,...}

step 1: new Map<1,1>

step 2: new Map<2,1>

step 3: find(Map.key==2) then (Map.value)++

就是這麼個思想啦。。。

而後就實踐了下，原本覺得10多分鐘就能搞定，沒想到前先後後弄了1個小時。。羞。。

 1 package cn.edu.bipt.hcol;
 2 
 3 import java.util.ArrayList;
 4 import java.util.HashMap;
 5 import java.util.Iterator;
 6 import java.util.List;
 7 import java.util.Map;
 8 import java.util.Set;
 9 
10 public class Founder {
11     
12     static int timeKeeper = 1;
13 
14     private List<Map<String, Integer>> mFunction(int n[]) {
15         List<Map<String, Integer>> mList = new ArrayList<Map<String, Integer>>();
16         HashMap<String, Integer> mMap;
17         
18         int target = -1;
19         int counter = 1;
20         String targetKey=null , counterKey=null;
21 
22         for (int x : n) {
23             if (mList.isEmpty()) {
24                 mMap = new HashMap<String, Integer>();
25                 mMap.put("target"+ x, x);
26                 mMap.put("counter" + x, counter);
27                 mList.add(mMap);
28             } else {
29                 boolean flag = false;
30                 for (int i = 0;i < mList.size();i++,target = -1 , targetKey = "",counterKey="") {
31                     timeKeeper++;
32                     mMap = (HashMap<String, Integer>) mList.get(i);
33                     Set mSet = mMap.keySet();
34                     Iterator it = mSet.iterator();
35                     while(it.hasNext()){
36                         String temp = (String)it.next();
37                         char c = temp.charAt(0);
38                         if(c=='t'){
39                             targetKey = temp;
40                             counterKey = (String)it.next();
41                         }else{
42                             counterKey = temp;
43                             targetKey = (String)it.next();
44                         }
45                     }
46                     target = mMap.get(targetKey);
47                     counter = mMap.get(counterKey);
48                     if(target == x){
49                         ++counter;
50                         mMap.put("counter" + target, counter);
51                         flag = true;
52                         break;
53                     }
54                 }
55                 if(!flag){
56                     counter = 1;
57                     mMap = new HashMap<String, Integer>();
58                     mMap.put("target"+ x, x);
59                     mMap.put("counter" + x, counter);
60                     mList.add(mMap);
61                 }
62             }
63         }
64         return mList;
65     }
66 
67     public static void main(String[] args) {
68         int test1n[]={1,1,1,1,3,2,2,3,2,2,3};
69         int test2n[] = new int[1000];
70         for(int i = 0;i<test2n.length;i++){
71             test2n[i] = (int)(Math.random()*10);
72         }
73         
74         List<Map<String, Integer>> mList = new Founder().mFunction(test2n);
75         
76         for(int x : test2n){
77             System.out.print(x+" ");
78         }
79         System.out.println();
80         
81         for(int i = 0;i < mList.size();i++){
82             HashMap<String, Integer> mMap = (HashMap<String, Integer>) mList.get(i);
83             Set<String> set = mMap.keySet();
84             Iterator<String> it = set.iterator();
85             while(it.hasNext()){
86                 String key = it.next();
87                 int value = mMap.get(key);
88                 System.out.print(key+":"+value+"   ");
89             }
90             System.out.println();
91         }
92         System.out.println("timeKeeper"+":"+timeKeeper);
93     }
94 }