1084. Broken Keyboard (20) [String operation] -- PAT (Advanced Level) Practise

1084. Broken Keyboard (20) [String operation] -- PAT (Advanced Level) Practise
Question Information1084. Broken Keyboard (20)

Time limit 200 MS
The memory limit is 65536 kB.
Code length limit: 16000 B
On a broken keyboard, some of the keys are worn out. So when you type some sentences, the characters corresponding to those keys will not appear on screen.

Now given a string that you are supposed to type, and the string that you are actually type out, please list those keys which are for sure worn out.

Input Specification:

Each input file contains one test case. for each case, the 1st line contains the original string, and the 2nd line contains the typed-out string. each string contains no more than 80 characters which are either English letters [A-Z] (case insensitive), digital numbers [0-9], or "_" (representing the space ). it is guaranteed that both strings are non-empty.

Output Specification:

For each test case, print in one line the keys that are worn out, in the order of being detected. the English letters must be capitalized. each worn out key must be printed once only. it is guaranteed that there is at least one worn out key.

Sample Input:
7_This_is_a_test
_ Hs_s_a_es
Sample Output:
7TI

Solutions

Question

AC code

#include 
  
   #include 
   
    #include 
    
     #include 
     
      using namespace std;int main(){    char s[100], a[100], r[100];    set
      
        st; scanf("%s%s", s, a); int len = strlen(s), cnt = 0; for (int i = 0; i < len; ++i){ if (NULL == strchr(a, s[i])){ if (st.insert(toupper(s[i])).second){ r[cnt++] = toupper(s[i]); } } } for (int i = 0; i < cnt; ++i){ putchar(r[i]); } return 0;}