#leetcode#38. Count and Say
阿新 • • 發佈:2018-12-27
The count-and-say sequence is the sequence of integers with the first five terms as following:
1. 1 2. 11 3. 21 4. 1211 5. 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"
1211
.Given an integer n, generate the nth term of the count-and-say sequence.
Note: Each term of the sequence of integers will be represented as a string.
Example 1:
Input: 1 Output: "1"
Example 2:
Input: 4 Output: "1211"
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public class Solution { public String countAndSay(int n) { String curStr = "1"; while(n > 1){ int i = 0; StringBuilder sb = new StringBuilder(); while(i < curStr.length()){ int count = 1; char curNum = curStr.charAt(i); while(i + 1 < curStr.length() && curStr.charAt(i + 1) == curStr.charAt(i)){ i++; count++; } sb.append(count); sb.append(curNum); i++; } curStr = sb.toString(); n--; } return curStr; } }