38. Count and Say

weixin_30662011

于 2017-01-11 14:14:00 发布

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原文链接：http://www.cnblogs.com/rocksolid/p/6273468.html

本文介绍了一种生成计数与描述序列的方法，通过迭代方式生成整数序列，该序列从1开始，后续每一项都是对前一项的描述。例如1被描述为“one 1”即11，11被描述为“two 1s”即21等。

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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.

class Solution(object):
    def countAndSay(self, n):
        """
        :type n: int
        :rtype: str
        """
        li=['1']
        newli=['1']
        for i in range(1,n):
            newli=[]
            count= 0
            temp= li[0]
            for x in li:
                if x==temp:
                    count+=1
                else:
                    newli.append(str(count))
                    newli.append(temp)
                    temp = x
                    count = 1
            else:
                newli.append(str(count))
                newli.append(temp)
            li=newli

        return ''.join(newli)