leetcode之Count and Say

这个题目关键是理解题目。别人是这样理解的。

1

1个1，即11

2个1，即21

1个2，1个1，即1211，

1个1,1个2,2个1，即111221，

3个1,2个2,1个1，即312211

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.

Show Tags

Show Similar Problems

// test38CountAndSay.cpp : 定义控制台应用程序的入口点。

//


#include "stdafx.h"
#include "string"
#include "iostream"


using std::cout;
using std::endl;
using std::string;
string countAndSay(int n);
string count(string temp);


int _tmain(int argc, _TCHAR* argv[])
{
string s = countAndSay(4);
return 0;
}


string countAndSay(int n) 
{
string result;
if (n == 1)
return "1";
else
{
result = "1";
for (int i = 1; i < n; i++)
{
result = count(result);
}
}
return result;


}
string count(string temp)
{
int n = temp.size();
char countNum;
int count = 0;
string result = "";
char current = temp[0];
for (auto i = 0; i < n; i++)
{
if (temp[i] == current)
{
count++;
continue;//相等就继续往后搜索
}
else
{   //不等则拼接后重新搜索，注意当前字符更新。
countNum = count + 48;//Int转字符型
result += countNum;
result += current;
count = 1;
current = temp[i];
}
}
//拼接最后搜索到的数字。
countNum = count + 48;
result += countNum;
result += current;
return result;
}