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.
Notice
The sequence of integers will be represented as a string.
Given n = 5, return "111221".
LeetCode上的原题，请参见我之前的博客Count and Say。
class Solution { public: /** * @param n the nth * @return the nth sequence */ string countAndSay(int n) { if (n < 1) return ""; string res = "1"; while (--n) { res.push_back('#'); string t = ""; int cnt = 1; for (int i = 1; i < res.size(); ++i) { if (res[i] == res[i - 1]) ++cnt; else { t += to_string(cnt) + res[i - 1]; cnt = 1; } } res = t; } return res; } };
本文转自博客园Grandyang的博客，原文链接：计数和读法[LintCode] Count and Say ，如需转载请自行联系原博主。