无旋Treap【模板】P3369

题目

详情见链接。

代码

 #include<cstdio>
 #include<iostream>
 #define outd(x) printf("%d\n",x)
 #define outld(x) printf("%lld\n", x)
 #define ls(x)  arr[x].child[0]
 #define rs(x)  arr[x].child[1]
 inline int read_int()
 {
     char c;
     int ret = , sgn = ;
     do { c = getchar(); } while ((c < '' || c > '') && c != '-');
     if (c == '-')  sgn = -;  else ret = c - '';
     while ((c = getchar()) >= '' && c <= '')  ret = ret *  + (c - '');
     return sgn * ret;
 }
 using namespace std;

 const int maxn =  + ;

 struct node
 {
     int child[], size, value, key;
 }arr[maxn];
 int tot;     //当前节点个数

 inline void push_up(int index)
 {
     arr[index].size = arr[ls(index)].size + arr[rs(index)].size + ;
 }

 void split(int root, int& x, int& y, int value)  //x中的小于或等于value，y中的大于value
 {
     if (!root) { x = y = ; return; }
     if (arr[root].value <= value) { x = root; split(rs(root), rs(x), y, value); }
     else { y = root; split(ls(root), x, ls(y), value); }
     push_up(root);
 }

 void merge(int&root, int x, int y)
 {
     if (!x || !y) { root = x + y; return; }     //其中一个为0，root等于另一个
     if (arr[x].key < arr[y].key) { root = x; merge(rs(root), rs(x), y); }
     else { root = y; merge(ls(root), x,ls(y)); }
     push_up(root);
 }

 inline void insert(int& root, int value)
 {
     int x = , y = , z = ++tot;
     arr[z].value = value, arr[z].size = , arr[z].key = rand();
     split(root, x, y, value);
     merge(x, x, z);
     merge(root, x, y);
 }

 inline void erase(int& root, int value)
 {
     int x = , y = , z = ;
     split(root, x, y, value);
     split(x, x, z, value - );        //z中全是value
     merge(z, ls(z), rs(z));
     merge(x, x, z);
     merge(root, x, y);
 }

 inline int Kth_number(int root, int k)
 {
     while (arr[ls(root)].size +  != k)
     {
         if (arr[ls(root)].size >= k)  root = ls(root);
         else { k -= (arr[ls(root)].size + ); root = rs(root); }
     }
     return arr[root].value;
 }

 inline int Get_rank(int& root, int value)
 {
     int x = , y = ;
     split(root, x, y, value - );
     int res = arr[x].size + ;
     merge(root, x, y);
     return res;
 }

 inline int Pre(int& root, int value)
 {
     int x = , y = ;
     split(root, x, y, value - );
     int res = Kth_number(x, arr[x].size);
     merge(root, x, y);    //merge回去
     return res;
 }

 inline int Suf(int& root, int value)
 {
     int x = , y = ;
     split(root, x, y,value);
     int res = Kth_number(y, );
     merge(root, x, y);
     return res;
 }

 int n, op, root;

 int main()
 {
     srand();
     n = read_int();
     while (n--)
     {
         op = read_int();
         if (op == )  insert(root, read_int());
         if (op == )  erase(root, read_int());
         if (op == )  outd(Get_rank(root, read_int()));
         if (op == )  outd(Kth_number(root, read_int()));
         if (op == )  outd(Pre(root, read_int()));
         if (op == )  outd(Suf(root, read_int()));
     }

     return ;
 } 

参考视频链接：https://www.bilibili.com/video/av46204315/?p=2