LeetCode(51)- Count and Say
3719 ワード
タイトル:
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.
構想
コード:
public class Solution {
public String countAndSay(int n) {
String str = "1";
for(int i = 1;i < n;i++){
int num = 1;
StringBuffer sb = new StringBuffer();
for(int j = 1;j < str.length();j++){
if(str.charAt(j) == str.charAt(j-1)){
num++;
}else{
sb.append(num).append(str.charAt(j-1));
num = 1;
}
}
sb.append(num).append(str.charAt(str.length()-1));
str = sb.toString();
}
return str;
}
}