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leetcode--Count and Say

2024-07-07 18:20:59   220人阅读

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.

?
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
public class Solution {
    /**It is simple problem.
     * @author Averill Zheng
     * @version 2014-06-07
     * @since JDK 1.7
     */
    public String countAndSay(int n) {
        String result = "1";
        for(int i = 1; i < n; ++i){
            StringBuffer resultBuffer = new StringBuffer();
            int length = result.length();
            char currentChar = result.charAt(0);
            int count = 0;
            for(int j = 0; j < length; ++j){
                if(currentChar != result.charAt(j)){
                    resultBuffer.append(count);
                    resultBuffer.append(currentChar - ‘0‘);
                    currentChar = result.charAt(j);
                    count = 1;
                }
                else
                    ++count;
            }
            resultBuffer.append(count);
            resultBuffer.append(currentChar - ‘0‘);
            result = resultBuffer.toString();
        }
        return result;
    }
}

　　


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