LeetCode 38. Count and Say 字串“閱讀式”擴張
阿新 • • 發佈:2019-01-02
題目:
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.
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public class Solution { public String countAndSay(int n) { String start = "1"; for(int i=2;i<=n;i++){ char[] mid = start.toCharArray(); String result = ""; int flag = 0; while(flag<mid.length){ char k = mid[flag]; flag++; int sum = 1; while(flag<mid.length&&mid[flag]==k){ sum++; flag++; } result += sum; result += k; } start = result; } return start; } }