PAT Advanced 1140 Look-and-say Sequence (20 分)

Look-and-say sequence is a sequence of integers as the following:

D, D1, D111, D113, D11231, D112213111, ...

where D is in [0, 9] except 1. The (n+1)st number is a kind of description of the nth number. For example, the 2nd number means that there is one D in the 1st number, and hence it is D1; the 2nd number consists of one D (corresponding to D1) and one 1 (corresponding to 11), therefore the 3rd number is D111; or since the 4th number is D113, it consists of one D, two 1's, and one 3, so the next number must be D11231. This definition works for D = 1 as well. Now you are supposed to calculate the Nth number in a look-and-say sequence of a given digit D.

Input Specification:

Each input file contains one test case, which gives D (in [0, 9]) and a positive integer N (≤ 40), separated by a space.

Output Specification:

Print in a line the Nth number in a look-and-say sequence of D.

Sample Input:

1 8

Sample Output:

1123123111

乙级真题

#include <iostream>

using namespace std;

string coun(string str){

    string res="";int coun=;

    for(int i=;i<str.length();i++){

        if(str[i]==str[i-]) coun++;

        else {

            res+=(str[i-]);

            res+=(coun+'');

            coun=;

        }

    }

    res+=str[str.length()-];res+=(coun+'');

    return res;

}

int main()

{

    string A;int B;

    cin>>A>>B;

    for(int i=;i<B;i++) A=coun(A);

    cout<<A;

    system("pause");

    return ;

}

巴特西

PAT Advanced 1140 Look-and-say Sequence (20 分)

Input Specification:

Output Specification:

Sample Input:

Sample Output:

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