36_leetcode_Count and Say

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.

1:特殊情况， n <= 0; 2: 统计相同字符连续出现的次数，并先保存次数，后保存字符；以这样的形式遍历数组；3:把最后统计的次数和字符保存到字符串中。

string countAndSay(int n)
{
if ( n <= 0)
{
return "";
}

string temp = "1";
string result = "1";

for(int i = 1; i < n; i++)
{
int count = 1;
int number = temp[0] - '0';
int k = 1;
result.clear();
for(; temp[k] != '\0'; k++)
{
if(temp[k] - '0' == number)
{
count++;
}
else
{
result.push_back(count + '0');
result.push_back(number + '0');
count = 1;
number = temp[k] - '0';
}
}

result.push_back(count + '0');
result.push_back(number + '0');
temp = result;
}

return result;
}