题解 | #反转单词顺序#

一般遇到反转的问题要优先考虑栈，利用先进后出的性质。本题可以先用split方法将strng拆成子字符串，然后压入栈，再弹出。要注意删掉最后的空格。

import java.util.*;
public class Solution {
    public String ReverseSentence(String str) {
        Stack<String> stack = new Stack<>();
        String[] sub = str.split(" ");
        for(String sub1:sub){
            stack.push(sub1);
        }
        String cur = new String();
        while(stack.size()>0){
            cur = cur + stack.pop()+" ";
        }
        cur = cur.substring(0,cur.length()-1);
        return cur;
    }
}