POJ2761---Feed the dogs (Treap求区间第k大)

题意 就是求区间第k大，区间 不互相包含。

尝试用treap解决一下 第k大的问题。

 #include <set>
 #include <map>
 #include <cmath>
 #include <ctime>
 #include <queue>
 #include <stack>
 #include <cstdio>
 #include <string>
 #include <vector>
 #include <cstdlib>
 #include <cstring>
 #include <iostream>
 #include <algorithm>
 using namespace std;
 typedef unsigned long long ull;
 typedef long long ll;
 const int inf = 0x3f3f3f3f;
 const double eps = 1e-;
 const int maxn = 1e5+;
 struct Node
 {
     Node *ch[];
     int key, siz, r;
     Node (int val)
     {
         ch[] = ch[] = NULL;
         siz = ;
         key = val;
         r = rand();
     }
     bool operator < (const Node &rhs)const
     {
         return r < rhs.r;
     }
     int cmp(int x)const
     {
         if (key == x)
             return -;
         return key > x ?  : ;
     }
     void maintain()
     {
         siz = ;
         if (ch[] != NULL)
             siz += ch[] -> siz;
         if (ch[] != NULL)
             siz += ch[] -> siz;
     }
 };
 void rotate(Node* &root, int d)
 {
     Node *tmp = root -> ch[d^];
     root -> ch[d^] = tmp -> ch[d];
     tmp -> ch[d] = root;
     root -> maintain();
     tmp -> maintain();
     root = tmp;
 }
 void insert (Node* &root, int x)
 {
     if (root == NULL)
         root = new Node (x);
     else
     {
         int d = x < root -> key ?  : ;
         insert(root -> ch[d], x);
         if (root -> ch[d] -> r > root -> r)
             rotate(root, d^);
     }
     root -> maintain();
 }
 void dele(Node* &root, int x)
 {
     int d = root -> cmp(x);
     if (d == -)
     {
         Node* tmp = root;
         if (root -> ch[] != NULL && root -> ch[] != NULL)
         {
             int d1 = (root -> ch[] -> r > root -> ch[] -> r  ?  : );
             rotate(root, d1);
             dele(root -> ch[d1], x);
         }
         else
         {
             if (root -> ch[] == NULL)
                 root = root -> ch[];
             else
                 root = root -> ch[];
             delete tmp;
         }
     }
     else
         dele(root -> ch[d], x);
     if (root != NULL)
         root -> maintain();
 }
 int Get_kth(Node* root,int k)
 {
     if (root == NULL || k <=  || k > root -> siz)
         return ;
     int s = (root -> ch[] == NULL ?  : root -> ch[] ->siz);
     if (s +  == k)
         return root -> key;
     else if (s >= k)
         return Get_kth(root -> ch[], k);
     else
         return Get_kth(root -> ch[], k - s -);
 }
 struct Query
 {
     int l, r, k,idx;
     bool operator < (const Query &rhs)const
     {
         return r < rhs.r;
         //return l < rhs.l || (l == rhs.l&&r < rhs.r);
     }
 }Q[];
 int a[], ans[];
 Node* treap;
 int main()
 {
     #ifndef ONLINE_JUDGE
         freopen("in.txt","r",stdin);
     #endif
     int n, m;
     while  (~scanf ("%d%d",&n, &m))
     {
         for (int i = ; i < n; i++)
             scanf ("%d", a+i+);
         for (int i = ; i < m; i++)
         {
             scanf ("%d%d%d",&Q[i].l, &Q[i].r, &Q[i].k);
             Q[i].idx = i;
             if (Q[i].l > Q[i].r)
                 swap(Q[i].l,Q[i].r);
         }
         sort (Q, Q+m);
         int index = Q[].l, lidx = ;
         for (int i = ; i < m; i++)
         {
             for (int j = lidx; j && j < min(Q[i].l, Q[i-].r+); j++)
                 dele(treap, a[j]);
             lidx = Q[i].l;
             for (int j = max(Q[i].l,index); j <= Q[i].r; j++)
             {
                 insert(treap, a[j]);
             }
             index = Q[i].r+;
             ans[Q[i].idx] = Get_kth(treap, Q[i].k);
 
         }
         for (int i = ; i < m; i++)
         {
             printf("%d\n",ans[i]);
         }
     }
     return ;
 }