1112 Stucked Keyboard（20 分）

On a broken keyboard, some of the keys are always stucked. So when you type some sentences, the characters corresponding to those keys will appear repeatedly on screen for k times.

Now given a resulting string on screen, you are supposed to list all the possible stucked keys, and the original string.

Notice that there might be some characters that are typed repeatedly. The stucked key will always repeat output for a fixed k times whenever it is pressed. For example, when k=3, from the string thiiis iiisss a teeeeeest we know that the keys i and e might be stucked, but s is not even though it appears repeatedly sometimes. The original string could be this isss a teest.

Input Specification:

Each input file contains one test case. For each case, the 1st line gives a positive integer k (1_. It is guaranteed that the string is non-empty.

Output Specification:

For each test case, print in one line the possible stucked keys, in the order of being detected. Make sure that each key is printed once only. Then in the next line print the original string. It is guaranteed that there is at least one stucked key.

Sample Input:

3
caseee1__thiiis_iiisss_a_teeeeeest

Sample Output:

ei
case1__this_isss_a_teest

#include 
#include 

using namespace std;

int main()
{
    int n;
    int start,len;
    string s,s1;
    scanf("%d\n",&n);
    getline(cin,s);
    string a = "abcdefghijklmnopqrstuvwxyz0123456789_";
    int flag[37]={0};
    int pri[37] = {0};
    for(int i=0;i<37;i++)
    {
        for(int j=0;j=1) {
                flag[i] = 1;
            }
        }
    }

    for(int i=0;i

note:

• str.replace()用法，str.find()用法

str.replace(开始位置，替换长度，替换为的字符串)
str.find(目标字符串，开始查找位置）

• 遍历时要记录每次找到的位置，不能每次从头查找，否则

3
eeeeeeeeeiiiiiiiii
输出结果为ei