今晚，终于自己把treap的实现写了一遍，感觉不错。加油。

  1 #include<cstdio>
  2 #include<iostream>
  3 #include<cstdlib>
  4 #define rep(i,j,k) for(int i = j; i <= k; i++ )
  5 using namespace std;
  6 int n = 0;
  7
  8 int read()
  9 {
 10     int s = 0, t = 1;
 11     char c = getchar();
 12     while( !isdigit(c) ){
 13         if( c == ‘-‘ ) t = -1;
 14         c = getchar();
 15     }
 16     while( isdigit(c) ){
 17         s = s * 10 + c - ‘0‘;
 18         c = getchar();
 19     }
 20     return s * t;
 21 }
 22
 23 struct node{
 24 node*ch[2];
 25 int size, key, r;
 26 node(int key):key(key){
 27     ch[0] = NULL, ch[1] = NULL, r = rand(),size = 1;
 28   }
 29 int cmp(int x) const{
 30     if( x == key ) return -1;
 31     return x < key ? 0 : 1;
 32   }
 33 void maintain() {
 34   size = 1;
 35   if( ch[0] != NULL ) size += ch[0] -> size;
 36   if( ch[1] != NULL ) size += ch[1] -> size;
 37 }
 38
 39 };
 40
 41 void rorate(node*& o,int d)
 42 {
 43     node*k = o->ch[d^1];
 44     o->ch[d^1] = k->ch[d];
 45     k->ch[d] = o;
 46     o->maintain();
 47     k->maintain();
 48     o = k;
 49 }
 50
 51 void insert(node*&u,int v)
 52 {
 53     if( u == NULL ){
 54         u = new node(v);
 55     }
 56     else {
 57         int d = u->cmp(v);
 58         insert(u->ch[d], v);
 59         if( u->ch[d]->r > u->r ){
 60             rorate(u,d^1);
 61         }
 62     }
 63     u->maintain();
 64 }
 65
 66 void remove(node*&u,int v)
 67 {
 68     if( u == NULL ) return;
 69     int d = u->cmp(v);
 70     if( d == -1){
 71         if( u->ch[0] == NULL ){
 72             u = u->ch[1];
 73         }
 74         else if( u->ch[1] == NULL ){
 75             u = u->ch[0];
 76         }
 77         else {
 78             int d2 = (u->ch[0]->r > u->ch[1]->r ? 1 : 0);
 79             rorate(u,d2);
 80             remove(u->ch[d2],v);
 81         }
 82     }
 83     else remove(u->ch[d],v);
 84     if( u != NULL ) u->maintain();
 85 }
 86
 87 bool infind(node*&u,int v)
 88 {
 89     while( u != NULL )
 90     {
 91         int d = u->cmp(v);
 92         if( d == -1 )return 1;
 93         u = u->ch[d];
 94     }
 95     return 0;
 96 }
 97
 98 node* find(node*u,int v)
 99 {
100     while( u != NULL )
101     {
102         int d = u->cmp(v);
103         if( d == -1 )return u;
104         u = u->ch[d];
105     }
106     return NULL;
107 }
108
109 int kth(node*& u,int k)
110 {
111     if( u == NULL|| k <= 0 || k > u->size ) return 0;
112     int d = u->ch[1] == NULL? 0 : u->ch[1]->size;
113     if( k == d+1 ) return u->key;
114     else {
115         if( d >= k ){
116             return kth(u->ch[1],k);
117         }
118         else return kth(u->ch[0],k-d-1);
119     }
120 }
121
122 int rfind(node*u,int x)
123 {
124     int z = 0;
125     while( u != NULL )
126     {
127         int d = u->cmp(x);
128         if( d == -1 )
129            return z + ( u->ch[1] == NULL ? 1 : u->ch[1]->size+1 );
130         if( d == 0) z += (u->ch[1] == NULL ? 1 : u->ch[1]->size+1);
131         u = u->ch[d];
132     }
133     if( u == NULL ) return 0;
134 }
135
136 int rank(node*&u,int x)
137 {
138     int k = rfind(u,x);
139     return k;
140 }
141
142 int pre(node*u,int x)
143 {
144     int t = rank(u,x);
145     if( !t ) return 0;
146     return kth(u,t+1);
147 }
148
149 int suc(node*&u,int x)
150 {
151     int t = rank(u,x);
152     if( !t ) return 0;
153     return kth(u,t-1);
154 }
155
156 int minl(node*&u)
157 {
158     return kth(u,n);
159 }
160
161 int maxl(node*&u)
162 {
163     return kth(u,1);
164 }
165
166 void print(node* u)
167 {
168     if( u->ch[0] != NULL ){
169         print(u->ch[0]);
170     }
171     cout<<u->key<<" ";
172     if( u->ch[1] != NULL ){
173         print(u->ch[1]);
174     }
175 }
176
177 int main()
178 {
179     node* root = NULL;
180      int x;
181      while( scanf("%d", &x) == 1 && x ){
182         insert(root,x);
183         n++;
184      }
185      cout<<n<<endl;
186     char c;
187     while( scanf("%c", &c) == 1 ){
188         if( c == ‘d‘ ){
189             int x = read();
190             remove(root,x);
191             n--;
192         }
193         else if( c == ‘k‘ ){
194             int x = read();
195             cout<<kth(root,x)<<endl;
196         }
197         else if( c == ‘r‘ ){
198             int x = read();
199             cout<<rank(root,x)<<endl;
200         }
201         else if( c == ‘p‘ ){
202             int x = read();
203             cout<<pre(root,x)<<endl;
204         }
205         else if( c == ‘s‘ ){
206             int x = read();
207             cout<<suc(root,x)<<endl;
208         }
209         else if( c == ‘m‘){
210             cout<<maxl(root)<<endl;
211         }
212         else if( c == ‘n‘ ){
213             cout<<minl(root)<<endl;
214         }
215         print(root);
216         cout<<endl<<endl;
217     }
218     return 0;
219 }