The count-and-say sequence is the sequence of integers beginning as follows:
- 1, 11, 21, 1211, 111221, ...
is read off as
- 1
or
- "one
- 1"
.
- 11
is read off as
- 11
or
- "two
- 1s"
.
- 21
is read off as
- 21
, then
- "one
- 2
or
- one 1"
.
- 1211
Given an integer n, generate the nth sequence.
Note: The sequence of integers will be represented as a string.
- public class Solution {
- public String countAndSay(int n) {
- if (n == 0)
- return "";
- StringBuffer sb = new StringBuffer("1");
- StringBuffer tempSB = new StringBuffer();
- for (int i = 1; i < n; i++) {
- int counter = 1;
- char tempChar = sb.charAt(0);
- for (int j = 1; j < sb.length(); j++) {
- if (sb.charAt(j) == tempChar)
- counter++;
- else {
- tempSB.append(""+counter + tempChar);
- tempChar = sb.charAt(j);
- counter = 1;
- }
- }
- tempSB.append(""+counter + tempChar);
- sb.delete(0, sb.length());
- sb.append(tempSB);
- tempSB.delete(0, tempSB.length());
- }
- return sb.toString();
- }
- }
或者
- public String countAndSay(int n) {
- if (n == 0) return "";
- StringBuffer sb = new StringBuffer("1");
- StringBuffer tempSB = new StringBuffer();
- for (int i = 1; i < n; i++) {
- int counter = 1;
- char tempChar = sb.charAt(0);
- for (int j = 1; j < sb.length(); j++) {
- if (sb.charAt(j) == tempChar)
- counter++;
- else {
- tempSB.append(Integer.toString(counter)+ tempChar);
- tempChar = sb.charAt(j);
- counter = 1;
- }
- }
- tempSB.append(Integer.toString(counter)+ tempChar);
- sb.delete(0, sb.length());
- sb.append(tempSB);
- tempSB.delete(0, tempSB.length());
- }
- return sb.toString();
- }
来源: http://www.bubuko.com/infodetail-2040928.html