求教一个算法实现！

xlwang_0903

问题描述起来很简单：就是咱们的手机九宫格输入按键，如果输入数字组合，求输出所有字母的组合。如2键有字幕abc，3键有字母def，输入23，输出就是{"ad","ae","af","bd","be","bf","cd","ce","cf"}。求教一个C语言实现的代码，谢谢！

lxyscls

1. char _2[3] = {'a', 'b', 'c'};
   
2. char _3[3] = {'d', 'e', 'f'};
   
3. 
   
4. int k = 0;
   
5. char r[9][3];
   
6. 
   
7. for (int i = 0; i < 3; i++) {
   
8.     for (int j = 0; j < 3; j++) {
   
9.         snprintf(r[k++], 3, "%c%c", _2[i], _3[j]);
   
10.     }
    
11. }

复制代码

xlwang_0903

回复 2# lxyscls
如果并不知道会输入几个数字的组合，那这个循环该如何设计呢？而且数字7和9还分别表示4个字母。

   

lxyscls

回复 3# xlwang_0903

1.     struct key {
   
2.         int num;
   
3.         char c[0];
   
4.     };
   
5. 
   
6.     struct key *_7 = malloc(sizeof(int)+4*sizeof(char));
   
7.     _7->num = 4; _7->c[0] = '?'; _7->c[1] = '?'; _7->c[2] = '?'; _7->c[3] = '?';
   
8.     for (int i = 0; i < _7->num; i++)
   
9.         ... ...
   
10.    

复制代码

dorodaloo

保持好奇心多学习

dorodaloo

回复 1# xlwang_0903
我来写一个

1. #include <ctype.h>
   
2. #include <stdio.h>
   
3. #include <stdlib.h>
   
4. #include <string.h>
   
5. 
   
6. char *key[] = {
   
7.     "", "", "abc", "def", "ghi", "jkl", "mno", "pqrs", "tuv", "wxyz",
   
8. };
   
9. void compose(char *keys);
   
10. void cpsFunc(unsigned index, char *keys, char *composedStr);
    
11. 
    
12. int main(int argc, char *argv[]) {
    
13.     char *test[] = {"001", "3", "02310", "23", "2b4", "357", "9925", "987654"};
    
14.     unsigned size = sizeof(test) / sizeof(char *);
    
15. 
    
16.     for (int i = 0; i < size; i++) {
    
17.         printf("input = %s\n", test[i]);
    
18.         compose(test[i]);
    
19.         printf("\n\n");
    
20.     }
    
21. }
    
22. 
    
23. void compose(char *keys) {
    
24.     unsigned size = strlen(keys);
    
25. 
    
26.     for (unsigned i = 0; i < size; i++)
    
27.         if (!isdigit(keys[i])) {
    
28.             fprintf(stderr, "'%c' NOT digit\n", keys[i]);
    
29.             return;
    
30.         }
    
31.     char composedStr[size + 1];
    
32.     memset(composedStr, 0, size + 1);
    
33.     cpsFunc(0, keys, composedStr);
    
34. }
    
35. 
    
36. void cpsFunc(unsigned index, char *keys, char *composedStr) {
    
37.     if (!*keys) {
    
38.         printf("%s ", composedStr);
    
39.         return;
    
40.     }
    
41.     if (!strlen(key[*keys - '0'])) {
    
42.         cpsFunc(index, keys + 1, composedStr);
    
43.         return;
    
44.     }
    
45. 
    
46.     for (char *alpha = key[*keys - '0']; *alpha; alpha++) {
    
47.         composedStr[index] = *alpha;
    
48.         cpsFunc(index + 1, keys + 1, composedStr);
    
49.     }
    
50. }
    

复制代码