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.
class Solution {
public:
string countAndSay(int n) {
string res = "1";
string cur = "1";
if (1 == n)
return res;
for (int i=1; i<n; i++)
{
res.clear(); //进行下次计算,情况当前
int nCurLen = cur.size();
for (int j=0; j<nCurLen; j++)
{
int nCount = 1;
while (cur[j]==cur[j+1] && j+1<nCurLen)
{
++nCount; // 计数+1
++j; // 字符后移
}
res += nCount+'0';
res += cur[j];
nCount =1;
}
cur = res;
}
return res;
}
};