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| #include <cstdio>
#include <algorithm>
using namespace std;
const int N = 16e4 + 10;
int n, m, rt, A[N];
struct Node
{
int p, sz, s[2];
} tr[N];
void pushup(int x)
{
tr[x].sz = tr[tr[x].s[0]].sz + tr[tr[x].s[1]].sz + 1;
}
void rotate(int x)
{
int y = tr[x].p, z = tr[y].p;
int k = x == tr[y].s[1];
tr[z].s[y == tr[z].s[1]] = x;
tr[x].p = z;
tr[tr[x].s[k ^ 1]].p = y;
tr[y].s[k] = tr[x].s[k ^ 1];
tr[y].p = x;
tr[x].s[k ^ 1] = y;
pushup(y);
pushup(x);
}
void splay(int x, int k)
{
while (tr[x].p != k)
{
int y = tr[x].p, z = tr[y].p;
if (z != k)
if ((y == tr[z].s[1]) ^ (x == tr[y].s[1]))
rotate(x);
else
rotate(y);
rotate(x);
}
if (!k)
rt = x;
}
int build(int l, int r)
{
if (l > r)
return 0;
int mid = l + r >> 1;
tr[A[mid]].sz = 1;
int t = build(l, mid - 1);
tr[t].p = A[mid];
tr[A[mid]].s[0] = t;
t = build(mid + 1, r);
tr[t].p = A[mid];
tr[A[mid]].s[1] = t;
pushup(A[mid]);
return A[mid];
}
int pre(int x)
{
splay(x, 0);
int u = tr[x].s[0];
if (!u)
return 0;
while (tr[u].s[1])
u = tr[u].s[1];
return u;
}
int nxt(int x)
{
splay(x, 0);
int u = tr[x].s[1];
if (!u)
return 0;
while (tr[u].s[0])
u = tr[u].s[0];
return u;
}
int get(int k)
{
int u = rt;
while (u)
{
if (tr[tr[u].s[0]].sz + 1 == k)
return u;
else if (tr[tr[u].s[0]].sz + 1 < k)
{
k -= tr[tr[u].s[0]].sz + 1;
u = tr[u].s[1];
}
else
u = tr[u].s[0];
}
return u;
}
int rnk(int x)
{
splay(x, 0);
return tr[tr[x].s[0]].sz + 1;
}
void print(int x)
{
if (tr[x].s[0])
print(tr[x].s[0]);
printf("%d ", x);
if (tr[x].s[1])
print(tr[x].s[1]);
}
int main()
{
scanf("%d%d", &n, &m);
for (int i = 1; i <= n; i++)
scanf("%d", &A[i]);
rt = build(1, n);
for (char op[10]; m; m--)
{
scanf("%s", op);
if (op[0] == 'T')
{
int s;
scanf("%d", &s);
int u = nxt(s);
if (!u)
{
swap(tr[s].s[0], tr[s].s[1]);
continue;
}
tr[tr[s].s[0]].p = u;
tr[u].s[0] = tr[s].s[0];
tr[s].s[0] = 0;
splay(u, 0);
}
else if (op[0] == 'B')
{
int s;
scanf("%d", &s);
int u = pre(s);
if (!u)
{
swap(tr[s].s[0], tr[s].s[1]);
continue;
}
tr[tr[s].s[1]].p = u;
tr[u].s[1] = tr[s].s[1];
tr[s].s[1] = 0;
splay(u, 0);
}
else if (op[0] == 'I')
{
int s, t;
scanf("%d%d", &s, &t);
if (!t)
continue;
int u = t == 1 ? nxt(s) : pre(s);
splay(u, s);
int k = u == tr[s].s[1];
Node tmp = tr[u];
tr[u].s[k] = s;
tr[s].p = u;
tr[u].s[k ^ 1] = tr[s].s[k ^ 1];
tr[tr[s].s[k ^ 1]].p = u;
tr[u].p = 0;
rt = u;
tr[s].s[0] = tmp.s[0];
tr[tmp.s[0]].p = s;
tr[s].s[1] = tmp.s[1];
tr[tmp.s[1]].p = s;
pushup(s);
pushup(u);
}
else if (op[0] == 'A')
{
int s;
scanf("%d", &s);
printf("%d\n", rnk(s) - 1);
}
else if (op[0] == 'Q')
{
int s;
scanf("%d", &s);
printf("%d\n", get(s));
}
}
return 0;
}
|