AcWing 827. 双链表
原题链接
简单
#include<iostream>
using namespace std;
const int N = 100010;
int m;
int e[N], l[N], r[N], idx;
void remove(int a)
{
r[l[a]] = r[a];
l[r[a]] = l[a];
}
void insert(int a, int x)
{
e[idx] = x;
l[idx] = a;
r[idx] = r[a];
l[r[a]] = idx;
r[a] = idx ++ ;
}
int main()
{
cin >> m;
r[0] = 1;
l[1] = 0;
idx = 2;
while(m -- )
{
string op;
int k, x;
cin >> op;
if(op == "R")
{
cin >> x;
insert(l[1], x);
}
else if(op == "L")
{
cin >> x;
insert(0, x);
}
else if(op == "IL")
{
cin >> k >> x;
insert(l[k + 1], x);
}
else if(op == "IR")
{
cin >> k >> x;
insert(k + 1, x);
}
else
{
cin >> k;
remove(k + 1);
}
}
for(int i = r[0]; i != 1; i = r[i])
printf("%d ", e[i]);
return 0;
}