题目来源:https://leetcode.com/problems/length-of-last-word/
问题描述
58. Length of Last Word
Easy
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.
Example:
Input: "Hello World"
Output: 5
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题意
给定一个字符串,求字符串中最后一个单词的长度
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思路
遍历每个字符,用整数cnt记录每个单词的长度。如果是第一个空格则用整数pre记录下上一个单词的长度,并将cnt清零,准备记录下一个单词的长度。遇到连续的多个空格,则第二个空格开始不处理。最后如果cnt == 0,则说明字符串最后有空格,则返回pre,否则返回cnt.
具体实现上,String的toCharArray方法可以将String转换为char[],从而用foreach方法遍历。代码如下:
for (char ch: str.toCharArray())
{
System.out.println(ch);
}
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代码
class Solution {
public int lengthOfLastWord(String s) {
int cnt = 0, pre = 0;
for (char ch: s.toCharArray())
{
if (ch == ' ')
{
if (cnt > 0)
{
pre = cnt;
cnt = 0;
}
}
else
{
cnt++;
}
}
return cnt == 0? pre:cnt;
}
}