LeetCode_Count and Say-优快云博客

本文链接：https://blog.youkuaiyun.com/sheng_ai/article/details/45722389

本文介绍了一种特殊的整数序列——计数并描述序列，并提供了一个C++实现方案。通过解析序列生成规则，逐步生成序列中的每一个数字。文章还附带了完整的代码实现。

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一.题目

Count and Say

Total Accepted: 41615 Total Submissions: 164918 My Submissions

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.

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二.解题技巧

这道题没有什么技巧，按照题目的要求一个数一个数生成就行了。不过要稍微注意下循环的次数。

三.实现代码

class Solution
{
private:
    string Deal(const string& StartString)
    {
        if (StartString.empty())
        {
            return string();
        }

        const int SIZE = StartString.size();

        stringstream Result;

        int Index = 0;
        int Count = 1;

        for (; Index < (SIZE - 1); Index++)
        {
            if (StartString[Index] != StartString[Index + 1])
            {
                Result << Count << StartString[Index];
                Count = 1;
            }
            else
            {
                Count++;
            }
        }

        Result << Count << StartString[Index];


     return Result.str();
    }
public:
    string countAndSay(int n)
    {
        string Result = "1";

        while(--n)
        {
            Result = Deal(Result);
        }

        return Result;

    }
};