Aha! Algorithms - Bubble Sort

《啊哈！算法》第 1 章第 2 节，冒泡排序的 Swift 实现

问题

给学生成绩排序，打印排序后的名字（和成绩）

解决

依次比较相邻的两个学生分数的大小，把低分的放到后面，直到最后一个尚未归位的学生

struct Student {
    let name: String
    let score: Int
}

var array: [Student] = [Student(name: "huhu", score: 5),
                        Student(name: "haha", score: 3),
                        Student(name: "xixi", score: 5),
                        Student(name: "hehe", score: 2),
                        Student(name: "momo", score: 8)]

let count = array.count

//N 个对象排序，只需要循环 N-1 遍
for i in 0..<count-1 {
    //循环比较直到最后一个尚未归位的对象
    for j in 0..<count-1-i {
        if array[j].score < array[j+1].score {
            swap(&array[j], &array[j+1])
        }
    }
}

for item in array {
    print("\(item.name): \(item.score)")
}

冒泡排序的时间复杂度是 O(N²)

代码在 GitHub