Count and Say@leetcode

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C++ 学习：The C++ Programming Language, 4th Edition
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Count and Say

AC Rate: 439/1647

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.

就是string的操作，那个tmp string做中间记录，一个n用于数，还有count，思路不难，要注意的就是string的操作，这里

str.append(str, char)是不行的，char不能append到string上，因为string 是const，而char是variable， append只能

用于string之间，而char添加直接用 str = str + char 加号就行了。

换上自己风格的代码看上去就是舒服些。。。

	class Solution {
	public:
	string countAndSay(int n) {
	string res = "1", tmp;
	for(int i=1; i<n; i++){
	int j=0;
	while(j<res.size()){
	int count = 0;
	char cur = res[j];
	while(j<res.size()&&res[j]==cur){
	count ++;
	j ++;
	}
	tmp.append(std::to_string(count));
	if(j==0) tmp.append("1");
	else
	tmp += res[j-1];
	}
	res.clear();
	res = tmp;
	tmp.clear();
	}
	return res;
	}
	};

view raw countandsay hosted with ❤ by GitHub

	class Solution {
	public:
	string countAndSay(int n) {
	// Note: The Solution object is instantiated only once and is reused by each test case.
	if(n<=0) return NULL;
	string res="1";
	while(n-->1)
	{
	string tmp;
	int count = 1;
	for(int i=1; i<res.size(); i++)
	{
	if(res[i]==res[i-1])
	{
	count++;
	}
	else
	{
	char tmp1='0'+count;
	tmp= tmp+tmp1;
	tmp= tmp+res[i-1];
	count=1;
	}
	}
	char tmp1 = '0'+count;
	tmp= tmp+ tmp1;
	tmp= tmp+res[res.size()-1];
	res = tmp;
	}
	return res;
	}
	};

view raw Count and Say hosted with ❤ by GitHub