Black Box(POJ 1442·TREAP实现)

 1 #include<set>
 2 #include<ctime>
 3 #include<queue>
 4 #include<cstdio>
 5 #include<cstdlib>
 6 #include<cstring>
 7 #include<iostream>
 8 #include<algorithm>
 9 using namespace std;
10 const int N = 100100;
11 #define L(i) (T[i].s[0])
12 #define R(i) (T[i].s[1])
13 #define For(i,n) for(int i=1;i<=n;i++)
14 #define Rep(i,l,r) for(int i=l;i<=r;i++)
15 
16 struct treap{
17     int size,s[2],v,pri;
18     void Sets(int x,int y){
19         size = 1;v = x;pri = y;
20     }
21 }T[N];
22 
23 int n,m,A[N],size,Lim,now,level = 0;
24 int tot,root;
25 int read(){
26     char ch = getchar(); int num = 0 , q = 1;
27     while(ch>‘9‘||ch<‘0‘){
28         if(ch==‘-‘) q = -1;
29         ch = getchar();
30     }
31     while(ch>=‘0‘&&ch<=‘9‘){
32         num = num * 10 + ch - ‘0‘;
33         ch = getchar();
34     }
35     return num * q;
36 }
37 
38 void Update(int i){
39     T[i].size = T[L(i)].size + T[R(i)].size + 1;
40 }
41 
42 void Rot(int &y,int f){
43     int x = T[y].s[!f];
44     T[y].s[!f] = T[x].s[f];
45     T[x].s[f]  = y;
46     Update(y);Update(x);
47     y = x;
48 }
49 
50 void Insert(int &i,int val){
51     if(!i){
52         T[i=++tot].Sets(val,rand());
53         return;
54     }
55     int f = T[i].v > val;
56     Insert(T[i].s[!f],val);
57     if(T[T[i].s[!f]].pri > T[i].pri) Rot(i,f);
58     else                             Update(i);
59 }
60 
61 int Rank(int i,int kth){
62     if(T[L(i)].size + 1 == kth) return i;
63     else if(T[L(i)].size >=kth) return Rank(L(i),kth);
64     else return Rank(R(i),kth - T[L(i)].size - 1);
65 }
66 
67 int main(){
68     srand(time(NULL));
69     n = read(); m = read();
70     For(i,n) A[i] = read();
71     For(i,m) {
72         Lim = read();
73         Rep(i,now+1,Lim) Insert(root,A[i]); now = Lim;
74         level++;printf("%d\n",T[Rank(root,level)].v);
75     }
76     return 0;
77 }