【剑指Offer】（字符串）翻转单词顺序列（翻转操作）

落日映苍穹つ 2022-03-12 15:44 191阅读 0赞

**题目链接**：[https://www.nowcoder.com/practice/3194a4f4cf814f63919d0790578d51f3?tpId=13&tqId=11197&tPage=3&rp=3&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking][https_www.nowcoder.com_practice_3194a4f4cf814f63919d0790578d51f3_tpId_13_tqId_11197_tPage_3_rp_3_ru_ta_coding-interviews_qru_ta_coding-interviews_question-ranking]

#### 题目描述 ####

牛客最近来了一个新员工Fish，每天早晨总是会拿着一本英文杂志，写些句子在本子上。同事Cat对Fish写的内容颇感兴趣，有一天他向Fish借来翻看，但却读不懂它的意思。例如，“student. a am I”。后来才意识到，这家伙原来把句子单词的顺序翻转了，正确的句子应该是“I am a student.”。Cat对一一的翻转这些单词顺序可不在行，你能帮助他么？

#### 解决方法 ####

class Solution { 
    public:
        string ReverseSentence(string str) { 
            if(str.size()<=1) return str;
            //[1]翻转整个字符串
            reverse(str,0,str.size()-1);
            //[2]单独翻转每个单词
            str+=' ';
            int begin=0;
            for(int i=0;i<str.size();i++){ 
                if(str[i]==' '){ 
                    reverse(str,begin,i-1);
                    begin=i+1;
                }
            }
            return str.substr(0,str.size()-1);
            
        }
        void reverse(string& str,int begin,int end){ 
            while(begin<end){ 
                char temp=str[begin];
                str[begin]=str[end];
                str[end]=temp;
                begin++;
                end--;
            }
        }
    };

[https_www.nowcoder.com_practice_3194a4f4cf814f63919d0790578d51f3_tpId_13_tqId_11197_tPage_3_rp_3_ru_ta_coding-interviews_qru_ta_coding-interviews_question-ranking]: https://www.nowcoder.com/practice/3194a4f4cf814f63919d0790578d51f3?tpId=13&tqId=11197&tPage=3&rp=3&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking