JZ-044 - Flip word order column

Flip word order column

Topic description

Niu Ke recently came to a new employee, Fish. Every morning, he always holds an English magazine and writes some sentences in the notebook. A colleague, Cat, was very interested in what Fish wrote. One day he borrowed it from Fish to read it, but he couldn't read it. For example, "student. a am I". Only later did I realize that the guy had reversed the order of the words in the sentence, and the correct sentence should be "I am a student."

• Cat is not good at reversing the order of these words one by one, can you help him?

title link : reverse word order column

code

/**
 * 标题：翻转单词顺序列
 * 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？
 * 题目链接：
 * https://www.nowcoder.com/practice/3194a4f4cf814f63919d0790578d51f3?tpId=13&&tqId=11197&rp=1&ru=/ta/coding-interviews&qru=/ta/coding-interviews/question-ranking
 */
public class Jz44 {

    public String reverseSentence(String str) {
        int n = str.length();
        char[] chars = str.toCharArray();
        int i = 0, j = 0;
        while (j <= n) {
            if (j == n || chars[j] == ' ') {
                reverse(chars, i, j - 1);
                i = j + 1;
            }
            j++;
        }
        reverse(chars, 0, n - 1);
        return new String(chars);
    }

    private void reverse(char[] c, int i, int j) {
        while (i < j) {
            swap(c, i++, j--);
        }
    }

    private void swap(char[] c, int i, int j) {
        char t = c[i];
        c[i] = c[j];
        c[j] = t;
    }

    public static void main(String[] args) {
        
    }
}

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