题解 | #句子逆序#

package main

import (
	"fmt"
	"os"
    "bufio"
)

func reverse(sb []byte, left int, right int) {
    // 对 sb[left, right] 区间进行反转，左闭右闭区间
    for i,j := left,right; i<j; i,j = i+1,j-1 {
        sb[i], sb[j] = sb[j], sb[i]
    }
}

func generateReverseSentence(s string) string {
    sb := []byte(s)
    size := len(sb)
    
    // 整体反转
    reverse(sb, 0, size-1)

    // 对每个单词进行反转
    slow, fast := 0, 0
    for fast < size {
        for fast < size && sb[fast] != ' ' {
            fast++
        }
        reverse(sb, slow, fast-1)
        slow = fast + 1
        fast = slow
    }

    return string(sb)
}

func main() {
    var s string

    inputReader := bufio.NewReader(os.Stdin)
    data, _, _ := inputReader.ReadLine()
    s = string(data)

    fmt.Println(generateReverseSentence(s))
}

// 本题为输入一个字符串，所以采用标准处理：inputReader.ReadLine()