【Leetcode】【python】Count and Say 报数

题目大意

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.

解题思路

刚开始题意没理解,题意是n=1时输出字符串1;n=2时,数上次字符串中的数值个数,因为上次字符串有1个1,所以输出11;n=3时,由于上次字符是11,有2个1,所以输出21;n=4时,由于上次字符串是21,有1个2和1个1,所以输出1211。

代码

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class Solution(object):

def count(self,s):
result = ''
count = 0
char = '#'
for i in s:
if i!=char:
if char!='#':
result+=str(count)+char
char = i
count = 1
else:
count+=1
result += str(count)+char
return result

def countAndSay(self, n):
"""
:type n: int
:rtype: str
"""
s='1'
for i in range(1, n):
s=self.count(s)
return s

总结