1 //自己簡化了 100%
 2 class Solution {
 3     public String getHint(String secret, String guess) {
 4         int bull = 0;
 5         int cow = 0;
 6         char[] arr1 = secret.toCharArray();
 7         char[] arr2 = guess.toCharArray();
 8         for(int i = 0; i < secret.length(); i++){
 9             if
 
(arr1[i] == arr2[i]){
10                 bull++;
11                 arr1[i] = ‘a‘;
12                 arr2[i] = ‘a‘;
13             }
14         }
15         int[] record1 = new int[10];
16         int[] record2 = new int[10];
17         for(int i = 0; i < arr1.length; i++){
18             if(arr1[i] != ‘a‘){
 
19                 record1[arr1[i] - ‘0‘]++;
20             }
21             if(arr2[i] != ‘a‘){
22                 record2[arr2[i] - ‘0‘]++;
23             }
24         }
25         for(int i = 0; i < 10; i++){
26             cow += Math.min(record1[i], record2[i]);
27         }
28         String res = "" + bull + "A" + cow + "B";
 
29         return res;
30         
31     }
32 }
33 
34 
35 
36 //Old
37 class Solution {
38     public String getHint(String secret, String guess) {
39         HashMap<Character, List<Integer>> map1 = new HashMap<>();
40         HashMap<Character, List<Integer>> map2 = new HashMap<>();
41         char[] arr1 = secret.toCharArray();
42         char[] arr2 = guess .toCharArray();
43         for(int i = 0; i < arr1.length; i++){
44             if(map1.containsKey(arr1[i])){
45                 map1.get(arr1[i]).add(i);
46             }else{
47                 List<Integer> list = new ArrayList<>();
48                 list.add(i);
49                 map1.put(arr1[i], list);
50             }
51         }
52         
53         for(int i = 0; i < arr2.length; i++){
54             if(map2.containsKey(arr2[i])){
55                 map2.get(arr2[i]).add(i);
56             }else{
57                 List<Integer> list = new ArrayList<>();
58                 list.add(i);
59                 map2.put(arr2[i], list);
60             }
61         }
62         int bull = 0, cow = 0;
63         for(char c : map2.keySet()){
64             if(!map1.containsKey(c)){
65                 continue;
66             }else{
67                 int size1 = map2.get(c).size();
68                 int size2 = map1.get(c).size();
69                 for(int pos : map2.get(c)){
70                     for(int i = 0; i < map1.get(c).size(); i++){
71                         if(pos == map1.get(c).get(i)){
72                             bull++;
73                             size1--;
74                             size2--;
75                         }
76                     }
77                 }
78                 cow += Math.min(size1, size2);
79             }
80         }
81         String res = "" + bull + "A" + cow + "B";
82         return res;
83          
84     }
85 }

299. Bulls and Cows