A1140. 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 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

#include<iostream>

#include<cstdio>

#include<string>

using namespace std;

int hashTB[] = {};

int main(){

    string ss = "";

    int D, N;

    cin >> D >> N;

    ss = ss + (char)('' + D);

    for(int i = ; i < N - ; i++){

        char pre = ss[];

        int cnt = ;

        string ss2 = "";

        for(int j = ; j < ss.length(); j++){

            if(ss[j] == pre){

                cnt++;

            }else{

                ss2 += pre;

                ss2 += (char)(cnt + '');

                pre = ss[j];

                cnt = ;

            }

        }

        ss2 += pre;

        ss2 += (char)(cnt + '');

        ss = ss2;

    }

    cout << ss;

    cin >> N;

    return ;

}

总结：

1、题意：题意不好理解时可以根据标题来猜意思。这题的意思让你看并且读出一个序列，如一个序列是18882111，则可以读为1个1，3个8，1个2，3个1，再将其写成位在前个数描述在后的序列：11，83，21，13。再对这个新序列进行描述。

巴特西

A1140. Look-and-say Sequence

Input Specification:

Output Specification:

Sample Input:

Sample Output:

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