PAT-2017年冬季考试-甲级-7-1 1140 Look-and-say Sequence (20分)

待我称王封你为后i 2023-02-22 07:41 59阅读 0赞

[1140 Look-and-say Sequence (20分)][1140 Look-and-say Sequence _20]  
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

AC代码：

#include <bits/stdc++.h>
    using namespace std;
    int main(){ 
    	string s;
    	int n,j;
    	cin>>s>>n;
    	for(int cnt=1;cnt<n;cnt++){ 
    		string t;
    		for(int i=0;i<s.length();i=j){ 
    			for( j=i;j<s.length() && s[j]==s[i];j++);
    			t+=s[i]+to_string(j-i);
    		}
    		s=t;
    	}
    	cout<<s;
    	system("pause");
        return 0;
    }

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzIxNDgwNjA3_size_16_color_FFFFFF_t_70]

[1140 Look-and-say Sequence _20]: https://pintia.cn/problem-sets/994805342720868352/problems/994805344490864640
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzIxNDgwNjA3_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200702094814662.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzIxNDgwNjA3,size_16,color_FFFFFF,t_70