PAT 1140 Look-and-say Sequence

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 this 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 one), therefore the 3rd number is D111; or since the 4th number is D113, it consists of one D, and both 1 ' s, and one 3, so the next number must be D11231. This definition works for D = 1 as well. Now is 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 an 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

#include<iostream> //水题using namespace std;int main(){    string d;    int n;    cin>>d>>n;    for(int i=1; i<n; i++){        char c=d[0];        string t;        int cnt=0;        for(int j=0; j<d.size(); j++){            if(d[j]==c) cnt++;            else{                t.append(1, c);                t.append(1, cnt+'0');                cnt=1;                c=d[j];             }        }        t.append(1, c);        t.append(1, cnt+'0');        d=t;    }    cout<<d<<endl;    

PAT 1140 Look-and-say Sequence