3 条题解

  • 0

    终于可以写一份A+B这么难的题的题解了。

    咦?竟然没有人写LCT的题解?

    Link-Cut Tree 会很伤心的!

    ORZ为了不让LCT伤心于是我来一份LCT的A+B题解吧!

    送上代码:
    ```cpp
    #include<iostream>
    #include<cstring>
    #include<cstdio>
    #include<cstring>
    using namespace std;
    struct node
    {
    int data,rev,sum;
    node *son[2],*pre;
    bool judge();
    bool isroot();
    void pushdown();
    void update();
    void setson(node *child,int lr);
    }lct[233];
    int top,a,b;
    node *getnew(int x)
    {
    node *now=lct+ ++top;
    now->data=x;
    now->pre=now->son[1]=now->son[0]=lct;
    now->sum=0;
    now->rev=0;
    return now;
    }
    bool node::judge(){return pre->son[1]==this;}
    bool node::isroot()
    {
    if(pre==lct)return true;
    return !(pre->son[1]==this||pre->son[0]==this);
    }
    void node::pushdown()
    {
    if(this==lct||!rev)return;
    swap(son[0],son[1]);
    son[0]->rev^=1;
    son[1]->rev^=1;
    rev=0;
    }
    void node::update(){sum=son[1]->sum+son[0]->sum+data;}
    void node::setson(node *child,int lr)
    {
    this->pushdown();
    child->pre=this;
    son[lr]=child;
    this->update();
    }
    void rotate(node *now)
    {
    node *father=now->pre,*grandfa=father->pre;
    if(!father->isroot()) grandfa->pushdown();
    father->pushdown();now->pushdown();
    int lr=now->judge();
    father->setson(now->son[lr^1],lr);
    if(father->isroot()) now->pre=grandfa;
    else grandfa->setson(now,father->judge());
    now->setson(father,lr^1);
    father->update();now->update();
    if(grandfa!=lct) grandfa->update();
    }
    void splay(node *now)
    {
    if(now->isroot())return;
    for(;!now->isroot();rotate(now))
    if(!now->pre->isroot())
    now->judge()==now->pre->judge()?rotate(now->pre):rotate(now);
    }
    node *access(node *now)
    {
    node *last=lct;
    for(;now!=lct;last=now,now=now->pre)
    {
    splay(now);
    now->setson(last,1);
    }
    return last;
    }
    void changeroot(node *now)
    {
    access(now)->rev^=1;
    splay(now);
    }
    void connect(node *x,node *y)
    {
    changeroot(x);
    x->pre=y;
    access(x);
    }
    void cut(node *x,node *y)
    {
    changeroot(x);
    access(y);
    splay(x);
    x->pushdown();
    x->son[1]=y->pre=lct;
    x->update();
    }
    int query(node *x,node *y)
    {
    changeroot(x);
    node *now=access(y);
    return now->sum;
    }
    int main()
    {
    scanf("%d%d",&a,&b);
    node *A=getnew(a);
    node *B=getnew(b);
    //连边 Link
    connect(A,B);
    //断边 Cut
    cut(A,B);
    //再连边orz Link again
    connect(A,B);
    printf("%d\n",query(A,B));
    return 0;
    }

    • @ 2021-06-04 19:43:45

      这个玩意不要脸从洛谷上复制题解下来,一被我方精神病院所抓获

    • @ 2021-07-17 16:45:21

      @eric451455: ???你不是精神病院的头号病人吗?

  • -3

    #include <iostream>
    using namespace std;
    int main()
    {
    int a,b;
    cin>>a>>b;
    int c=a+b;
    cout<<c<<endl;
    return 0;
    }

  • -7

    #include <iostream>

    using namespace std;

    int main()
    {

    int x,y;
    cin>>x>>y;
    cout<<x+y<<endl;
    return 0;
    }

    • @ 2021-03-01 15:29:41

      我没做错为啥给我点负赞

    • @ 2021-07-19 11:14:05

      @eric451455: 因为你是精神病院头号病人

  • 1

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