LeetCode38 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.（Easy）

分析:

按照题目要求以此生成新串即可，注意第一个是串是1，即下标从1开始。

同时，复习使用to_string.

代码：

class Solution {
public:
string countAndSay(int n) {
string s = "1";
for (int i = 1; i < n; ++i) {
int count = 1;
string temp;
for (int j = 0; j < s.size(); ++j) {
if (j == s.size() - 1 || s[j] != s[j + 1]) {
temp += to_string(count);
temp += s[j];
count = 1;
}
else {
count ++;
}
}
s = temp;
}
return s;
}
};