leetcode 151. Reverse Words in a String --------- java

Given an input string, reverse the string word by word.

For example,
Given s = "the sky is blue",
return "blue is sky the".

Update (2015-02-12):
For C programmers: Try to solve it in-place in O(1) space.

倒序字符串。

注意使用BufferString，因为如果使用String的话，会多次建立对象，会很慢。

public class Solution {

    public String reverseWords(String s) {

        int len = s.length();

        if( len == 0)

            return s;

        StringBuffer result = new StringBuffer() ;

        int end = len-1,start = 0;

        while( end >= 0 && s.charAt(end) == ' ')

            end--;

        if( end == -1)

            return result.toString();

        while( start < len && s.charAt(start) == ' ')

            start++;

        int pos = end+1;

        for( int i = end ; i >= start ; i-- ){

            if( s.charAt(i) == ' ') {

                result.append(s.substring(i+1,pos));

                result.append(" ");

                while (i < end && s.charAt(i) == ' ')

                    i--;

                i++;

                pos = i;

            }

        }

        result.append(s.substring(start,pos));

        return result.toString();

    }

}

巴特西

leetcode 151. Reverse Words in a String --------- java

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