刷题-Count and Say-缺python

最新推荐文章于 2025-12-15 08:57:28 发布

原创最新推荐文章于 2025-12-15 08:57:28 发布 · 222 阅读

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文章标签：

#java #python #string #stringbuffer

本文深入探讨了 Count and Say 序列的生成原理，并提供了 Java 和 Python 的实现代码，详细解释了算法逻辑及其实现细节。

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.

java解法:

public class Solution {
public String countAndSay(int n) {
if (n<1) return null;
if (n==1) return "1";
String str = "1";
StringBuffer sb = new StringBuffer();
for (int j = 1 ;j < n;j++){
int count = 1;
for (int i = 1;i < str.length();i++){
if (str.charAt(i) == str.charAt(i-1)){
count++;
}
else{
sb.append(count);
sb.append(str.charAt(i-1));
count=1;
}

}
sb.append(count);
sb.append(str.charAt(str.length() - 1));
str = sb.toString();
sb.setLength(0);
}

return str;

}
}