单链表的基本操作

 826. 单链表 - AcWing题库

#include<bits/stdc++.h>
using namespace std;
const int N = 1e5 + 9 ;

int head, e[N], ne[N], idx;

void init()
{
    head = -1;
}

void add_head(int x)  // 插入头节点
{
    e[idx] = x, ne[idx] = head, head = idx ++ ;
}

void add_k(int k, int x)
{
    e[idx] = x, ne[idx] = ne[k], ne[k] = idx ++;
}

void remove(int k)
{
    ne[k] = ne[ne[k]];
}

int main()
{
    init();
    
    int m ; cin >> m;
    while (m -- )
    {
        char op;
        int k, x;
        cin >> op;
        if(op == 'H')
        {
            cin >> x;
            add_head(x);
        }
        else if(op == 'I')
        {
            cin >> k >> x;
            add_k(k - 1, x);
        }
        else
        {
            cin >> k;
            if(!k) head = ne[head];
            else remove(k - 1);
        }
    }
    
    for(int i = head; i != -1; i = ne[i]) cout << e[i] << ' ';
    cout << endl ;
    return 0;
}