[LeetCode] 38. Count and Say_Easy
The count-and-say sequence is the sequence of integers with the first five terms as following:
1. 1
2. 11
3. 21
4. 1211
5. 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 term of the count-and-say sequence.
Note: Each term of the sequence of integers will be represented as a string.
Example 1:
Input: 1
Output: "1"
Example 2:
Input: 4
Output: "1211" 1. Constraints
1)n >= 1 edge case n == 1: return '1' 2. Ideas
recursive helper() , helper()是一个能count and say 之前的string 3. Code
class Solution(object):
def countAndSay(self, n):
"""
:type n: int
:rtype: str
"""
def helper(n, s):
if n == 1: return s
pre, i , temp, count = s[0], 0, "", 0
while i < len(s):
if s[i] == pre:
count += 1
else:
temp += str(count) + pre
count = 1
pre = s[i]
i += 1
if i == len(s):
temp += str(count) +pre
return helper(n-1, temp)
ans = ""
return helper(n, '')
[LeetCode] 38. Count and Say_Easy的更多相关文章
- LeetCode - 38. Count and Say
38. Count and Say Problem's Link ------------------------------------------------------------------- ...
- LeetCode 38 Count and Say(字符串规律输出)
题目链接:https://leetcode.com/problems/count-and-say/?tab=Description 1—>11—>21—>1211—>111 ...
- [LeetCode] 38. Count and Say 计数和读法
The count-and-say sequence is the sequence of integers with the first five terms as following: 1. 1 ...
- Java [leetcode 38]Count and Say
题目描述: The count-and-say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211, ...
- [leetcode]38. Count and Say数数
The count-and-say sequence is the sequence of integers with the first five terms as following: 1. 1 ...
- Leetcode 38 Count and Say 传说中的递推
class Solution { public: vector<string> vs_; Solution(){ "); vs_.push_back(t); ; i< ;+ ...
- leetcode 38 Count and Say ---java
这道题主要就是求一个序列,题目得意思就是 1 --> 11 --> 21 --> 1211 --> 111221 --> 312211 --> ..... 1个 ...
- LeetCode - 38. Count and Say(36ms)
The count-and-say sequence is the sequence of integers with the first five terms as following: 1. 1 ...
- LeetCode题解38.Count and Say
38. Count and Say The count-and-say sequence is the sequence of integers beginning as follows: 1, 11 ...
随机推荐
- canvas - drawImage()方法绘制图片不显示的问题
canvas有个很强大的api是drawImage()(w3c): 他的主要功能就是绘制图片.视频,甚至其他画布等. 问题: 慕名赶来,却一脚踩空,低头一看,地上一个大坑. 事情是这样的,在我看完 ...
- JavaScript 浮点数陷阱及解法
众所周知,JavaScript 浮点数运算时经常遇到会 0.000000001 和 0.999999999 这样奇怪的结果,如 0.1+0.2=0.30000000000000004.1-0.9=0. ...
- EXCEL通俗易懂讲公式(一):sumif,sumifs,countif,countifs
最近公司招了一批新人,excel基本都是小白阶段,以前用过的也就是画个课程表,没做过什么数据统计和文本计算等工作.因此各种问题都来了,什么vlookup,offset,连条件求和的sumif也不会用, ...
- 跟bWAPP学WEB安全(PHP代码)--PHP代码注入
---恢复内容开始--- 背景 今天我们换一个方式来分析这个漏洞,从渗透的角度去搞. 渗透过程 测试漏洞 先来看看,观察URL是:http://192.168.195.195/bWAPP/phpi.p ...
- MFC修改窗口无标题和标题信息,修改执执行文件图标
一.创建MFC后 窗口显示的是 无标题-工程名 修改方法在网上看到了几种,下面介绍下比较简单的一种: 1.在MianFrame.c文件中找到这个函数 BOOL CMainFrame::PreCreat ...
- Python - 3MySQL 数据库连接
Python3 MySQL 数据库连接 本文我们为大家介绍 Python3 使用 PyMySQL 连接数据库,并实现简单的增删改查. 什么是 PyMySQL? PyMySQL 是在 Python3.x ...
- Shell sleep指定延迟时间
可以给时间,让上一条命令执行完毕后,并且退出 sleep 1 睡眠1秒sleep 1s 睡眠1秒sleep 1m 睡眠1分sleep 1h 睡眠1小时
- Spark2 oneHot编码--标准化--主成分--聚类
1.导入包 import org.apache.spark.sql.SparkSession import org.apache.spark.sql.Dataset import org.apache ...
- OOA/D 01
建筑师一般不会为一栋100层的楼添加一个新的地下室,因为成本太高无疑会失败,但软件系统里提出类似改动需求时,他们通常都不会多想一下,相反他们会说:这只是一个简单的编程问题 可总会有一些看似极难完成.但 ...
- CentOS 6U7分区大于2TB的磁盘以及挂载大于16TB分区磁盘的解决方案
一.内容介绍1.问题描述1).问题一 CentOS 6.x 在格式化大于16TB的ext4分区时,会提示如下错误: mke2fs 1.41.12 (17-May-2010)mkfs.ext4: Siz ...