1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
| const int N = 5e5 + 10, M = 3e7 + 10;
struct Node
{
int s[2], v, w, sz;
void init (int k)
{ s[0] = s[1] = 0, v = k, w = rand(), sz = 1; }
} tr[M];
int m, rt[N], idx;
void pushup (int x) { tr[x].sz = tr[tr[x].s[0]].sz + tr[tr[x].s[1]].sz + 1; }
int merge (int x, int y)
{
if (!x || !y) return x + y;
if (tr[x].w < tr[y].w)
{
tr[++idx] = tr[x]; x = idx;
tr[x].s[1] = merge(tr[x].s[1], y);
pushup(x);
return x;
}
else
{
tr[++idx] = tr[y]; y = idx;
tr[y].s[0] = merge(x, tr[y].s[0]);
pushup(y);
return y;
}
}
void split (int u, int k, int &x, int &y)
{
if (!u) return void(x = y = 0);
tr[++idx] = tr[u], u = idx;
if (tr[u].v <= k) x = u, split(tr[u].s[1], k, tr[u].s[1], y);
else y = u, split(tr[u].s[0], k, x, tr[u].s[0]);
pushup(u);
}
void insert (int &u, int k)
{
int x, y;
split(u, k, x, y);
tr[++idx].init(k);
u = merge(merge(x, idx), y);
}
void remove (int &u, int k)
{
int x, y, z;
split(u, k, x, z);
split(x, k - 1, x, y);
y = merge(tr[y].s[0], tr[y].s[1]);
u = merge(merge(x, y), z);
}
int rnk (int &u, int k)
{
int x, y;
split(u, k - 1, x, y);
int res = tr[x].sz + 1;
u = merge(x, y);
return res;
}
int kth(int u, int k)
{
while (u)
{
if (k <= tr[tr[u].s[0]].sz) u = tr[u].s[0];
else if (k == tr[tr[u].s[0]].sz + 1) return u;
else k -= tr[tr[u].s[0]].sz + 1, u = tr[u].s[1];
}
}
int pre (int &u, int k)
{
int x, y;
split(u, k - 1, x, y);
int res = kth(x, tr[x].sz);
u = merge(x,y);
return res;
}
int nxt(int &u, int k)
{
int x, y;
split(u, k, x, y);
int res = kth(y, 1);
u = merge(x, y);
return res;
}
|