LeetCode笔记:58. Length of Last Word
2016-11-29 09:19
351 查看
问题:
Given a string s consists of upper/lower-case alphabets and empty space characters ’ ‘, return the length of last word in the string.If the last word does not exist, return 0.
Note: A word is defined as a character sequence consists of non-space characters only.
For example,
Given s = “Hello World”,
return 5.
大意:
给出一个由大小写字母和空格组成的字符串s,返回其最后一个单词的长度。如果最后一个单词不存在,返回0。
注意:单词是指仅有非空格字符组成的序列。
例子:
给出 s = “Hello World”,
返回 5。
思路:
题目并不难,只是要注意,我在用测试用例尝试的时候发现,如果给出的字符串最后是空格,也会取空格前最后一个单词的长度,也就是说即使最后是多个空格,只要前面还有单词,就将其视为最后一个单词。我的做法是遍历数组,遇到字符串第一个就是字母或者说字母前一个字符是空格时,就将其视为一个单词的开始,令结果回到1,重新计算长度,其余遇到字母就将结果加一,遇到空格就不管了。
代码(Java):
public class Solution { public int lengthOfLastWord(String s) { int length = 0; char[] arr = s.toCharArray(); for (int i = 0; i < arr.length; i++) { if (i == 0) { if (arr[i] != ' ') length ++; } else if (arr[i-1] == ' ' && arr[i] != ' ') length = 1; else if (arr[i] != ' ') length ++; } return length; } }
他山之石:
public class Solution { public int lengthOfLastWord(String s) { int len = s.length(); int i = len -1; int empty = 0; if(s == null || len == 0) return 0; while(i>=0 && s.charAt(i)==' '){ i--; empty++; } while(i>=0 && s.charAt(i)!=' ') i--; return len- empty - (i+1); } }
这个做法是从后往前遍历字符串,末尾如果有空格,先把空格去除干净,然后取字母的长度,再次遇到空格打止,因为是从后往前遍历,不需要全部遍历完整个字符串,所以会快一点。
合集:https://github.com/Cloudox/LeetCode-Record
版权所有:http://blog.csdn.net/cloudox_
相关文章推荐
- [Leetcode] 58. Length of Last Word
- leetcode笔记:Length of Last Word
- 【一天一道LeetCode】#58. Length of Last Word
- leetcode 58. Length of Last Word
- 【LeetCode】58. Length of Last Word
- Leetcode #58. Length of Last Word 末尾词长 解题报告
- LeetCode 58. Length of Last Word
- [leetcode] 58. Length of Last Word
- [leetcode] 【字符串】58. Length of Last Word
- [leetcode] 58. Length of Last Word 解题报告
- leetcode-58. Length of Last Word
- LeetCode 58. Length of Last Word
- leetcode-java-58. Length of Last Word
- 58. Length of Last Word Leetcode Python
- <LeetCode OJ> 58. Length of Last Word
- Leetcode:58. Length of Last Word(JAVA)
- LeetCode *** 58. Length of Last Word
- 【leetcode】58. Length of Last Word
- [Leetcode]58. Length of Last Word
- LeetCode 58. Length of Last Word(最后一个单词的长度)