【leetcode】Count and Say （easy）

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.

十天没做题了，赶快秒个小题练练手。

思路：就是数每种数字出现了几次。

string countAndSay(int n) {
string s = "1";
while(--n) //从1开始计数
{
string stmp;
char c[10];
for(int i = 0; i < s.length(); )
{
int count = 0;
char cur = s[i];
while(i < s.length() && s[i] == cur) //数当前重复出现的数字
{
count++;
i++;
}
sprintf(c, "%d%d", count, cur - '0');
stmp += c;
}
s = stmp;
}
return s;
}