Question

我想实现链表。我写了一个插入列表方法，打印方法，但反向打印有问题。主要问题是反向打印打印正常列表，而不是反转：

#include <iostream>

struct Node
{
    int value;
    struct Node *next;
};

struct List
{
    struct Node *first, *last;
};

Node* node(int v)
{
    Node *newNode = new Node();
    newNode->value = v;
    newNode->next = NULL;
    return newNode;
}

List*  list()
{
    List *newList = new List();
    newList->first = NULL;
    newList->last = NULL;
    return newList;
}

List*  insert(List* s, Node* n)
{
    if (s->last == NULL)
    {
        n->next = s->last;
        s->last = n;
        s->first = n;
        return s;
    }

    s->last->next = n;
    s->last = s->last->next;
    return s;
}

void  print(List* s)
{
    Node *tmp = s->first;
    while(tmp)
    {
        std::cout << tmp->value << ' ';
        tmp = tmp->next;
    }
    std::cout << '\n';
}

void reverse_print(List* s)
{
    if(s->first == NULL)
    {
        std::cout << '\n';
        return;
    }

    else
    {
        std::cout << s->first->value << ' ';
        s->first = s->first->next;
        reverse_print(s);
    }
}

int main(int argc, char *argv[])
{
    List *myList2;
    myList2 = list();

    myList2 = insert(myList2, node(3));
    myList2 = insert(myList2, node(5));
    myList2 = insert(myList2, node(7));
    myList2 = insert(myList2, node(9));
    myList2 = insert(myList2, node(5));
    myList2 = insert(myList2, node(34));
    myList2 = insert(myList2, node(67));

    print(myList2);

    reverse_print(myList2);
}

Answer 1

您不应修改正在打印的列表。
您应首先以递归方式打印“列表的其余部分”。

最好的方法是为打印节点设置单独的功能：

var label = UILabel()

var animator = UIDynamicAnimator()



//magenta
let color = UIColor(red: 229.0/255, green: 0.0/255, blue: 81.0/255, alpha: 1.0)

//größe
let size : CGFloat = 100

// set yPosition to be a random number between 20.0 and 220.0
let xPosition : CGFloat = CGFloat( arc4random_uniform(200))+20
//        let bubble = UIView()

func bubble(let name: String){


    //magenta
    let color = UIColor(red: 229.0/255, green: 0.0/255, blue: 81.0/255, alpha: 1.0)

    //size
    let size : CGFloat = 100

    // set yPosition to be a random number between 20.0 and 220.0
    let xPosition : CGFloat = CGFloat( arc4random_uniform(200))+20
    //        let bubble = UIView()

    label.frame = (CGRect(x: xPosition, y: 320, width: size, height: size))
    label.layer.cornerRadius = label.frame.height/2
    label.layer.masksToBounds = true
    label.backgroundColor = color
    label.textColor = UIColor.whiteColor()

    label.text = name.uppercaseString
    label.textAlignment = .Center
    label.font = UIFont.boldSystemFontOfSize(12)

}


func gravity(){
    let gravity = UIGravityBehavior(items: [label])
    animator.addBehavior(gravity)
    let collision = UICollisionBehavior(items: [label])
    collision.translatesReferenceBoundsIntoBoundary = true
    animator.addBehavior(collision)
    let behavior = UIDynamicItemBehavior(items: [label])
    behavior.elasticity = 0.35
    animator.addBehavior(behavior)

}

Answer 2

更改

else
    {
        std::cout << s->first->value << ' ';
        s->first = s->first->next;
        reverse_print(s);
    }

到

else
    {
        reverse_print(s);
        s->first = s->first->next;
        std::cout << s->first->value << ' ';   
    }

应该可以帮助您有效地使用递归。

用C ++反转打印链表

2 个答案: