diff algorithm swift version

A few days ago, I used chatgpt to generate the diff algorithm, coupled with the concise syntax of swift, it can be called the icing on the cake. Here is the code:

func diff<T: Hashable>(old: [T], new: [T]) -> (added: [T], removed: [T], moved: [(from: Int, to: Int)]) {
    
    
    var added = [T]()
    var removed = [T]()
    var moved = [(from: Int, to: Int)]()
    
    // 将`old`集合内的元素转换为map形式去处理，就是元素本身e与下标index作为一组迭代数据，下同
    var oldIndexDict = [T: Int]()
    for (index, element) in old.enumerated() {
    
    
        oldIndexDict[element] = index
    }
    
    var newIndexDict = [T: Int]()
    for (index, element) in new.enumerated() {
    
    
        newIndexDict[element] = index
    }
    
    // 对`old`集合进行迭代，如果迭代元素e在`old`集合与`new`中的对应的下标均不存在，说明该元素e已被移除，需要将其放入`removed`集合中
    // 如果迭代元素e在`old`集合与`new`中的对应的下标均存在，则记录二者的下标，判断二者下标是否相同，相同说明`new`集合与`old`集合在同一下标下对应的元素e是同一个对象无需标记
    // 而不相同则意味着迭代元素e被移动了位置，需要将其放入`moved`集合中
    for element in old {
    
    
        if let oldIndex = oldIndexDict[element], let newIndex = newIndexDict[element] {
    
    
            if oldIndex != newIndex {
    
    
                moved.append((from: oldIndex, to: newIndex))
            }
        } else {
    
    
            removed.append(element)
        }
    }
    
    // 对new集合进行迭代，判断old集合是否存在new集合迭代元素e，e不在old中说明这是新增的元素
    // 需要将其放入`added`集合中
    for element in new {
    
    
        if !old.contains(element) {
    
    
            added.append(element)
        }
    }
    
    return (added: added, removed: removed, moved: moved)
}

use:

let a1 = ["a", "b", "c", "d"]
let a1 = ["b", "a", "c", "e"]
print(diff(a1, a2))