LeetcodeCount and Say

Posted 2020-07-19 wuezs

题目链接：https://leetcode.com/problems/count-and-say/

题目：

The count-and-say sequence is the sequence of integers beginning as follows:
1, 11, 21, 1211, 111221, ...

1 is read off as "one 1" or 11.
11 is read off as "two 1s" or 21.
21 is read off as "one 2, then one 1" or 1211.

Given an integer n, generate the nth sequence.

Note: The sequence of integers will be represented as a string.

思路：

题目看懂了就好做了。。

算法：

public String countAndSay(int n) {  
    String r = "1";  
    for (int i = 1; i < n; i++) {  
        String t = "";  
        int count = 0;  
        String flag = r.charAt(0) + "";  
        for (int j = 0; j < r.length(); j++) {  
            if ((r.charAt(j) + "").equals(flag)) {  
                count++;  
            } else {  
                t += count + "" + flag;  
                flag = r.charAt(j) + "";  
                count = 1;  
            }  
        }  
        t += count + "" + flag;  
        r = t;  
    }  
    return r;  
}