hdu 3999 二叉排序树

  1 #include <iostream>
  2 #include <cstdio>
  3 using namespace std;
  4 
  5 int n, cnt;
  6 
  7 struct Node 
  8 {
  9     Node * ch[2];
 10     int v;
 11     bool cmp( int x )
 12     {
 13         if ( x == v ) return -1;
 14         return x < v ? 0 : 1;
 15     }
 16 };
 17 
 18 Node * root;
 19 
 20 void insert( Node * & o, int x )
 21 {
 22     if ( o == NULL )
 23     {
 24         o = new Node ();
 25         o->ch[0] = o->ch[1] = NULL;
 26         o->v = x;
 27         return ;
 28     }
 29     int d = o->cmp(x);
 30     if ( d == -1 ) return ;
 31     insert( o->ch[d], x );
 32 }
 33 
 34 /*
 35 Node * find( Node * o, int x )
 36 {
 37     if ( o == NULL ) return NULL;        
 38     int d = o->cmp(x);
 39     if ( d == -1 ) return o;        
 40     return find( o->ch[d], x );
 41 }
 42 
 43 void remove( Node * & o, int x )
 44 {
 45     if ( o == NULL ) return ;
 46     int d = o->cmp(x);
 47     if ( d == -1 )
 48     {
 49         if ( o->ch[0] == NULL )
 50         {
 51             Node * tmp = o;
 52             o = o->ch[1];
 53             delete tmp;
 54         }
 55         else if ( o->ch[1] == NULL )
 56         {
 57             Node * tmp = o;
 58             o = o->ch[0];
 59             delete tmp;
 60         }
 61         else
 62         {
 63             Node * p = o, * q = o->ch[0];
 64             while ( q->ch[1] != NULL )
 65             {
 66                 p = q;
 67                 q = q->ch[1];
 68             }
 69             o->v = q->v;
 70             if ( p != o )
 71             {
 72                 p->ch[1] = q->ch[0];
 73                 delete q;
 74             }
 75             else
 76             {
 77                 p->ch[0] = q->ch[0];
 78                 delete q;
 79             }
 80         }
 81     }
 82     else
 83     {
 84         remove( o->ch[d], x );
 85     }
 86 }
 87 */
 88 
 89 void free( Node * o )
 90 {
 91     if ( o != NULL )
 92     {
 93         free(o->ch[0]);
 94         free(o->ch[1]);
 95         delete o;
 96     }
 97 }
 98 
 99 void visit( Node * o )
100 {
101     cnt++;
102     printf("%d", o->v);
103     if ( cnt != n ) putchar(‘ ‘);
104     else putchar(‘\n‘);    
105 }
106 
107 void preorder( Node * o )
108 {
109     if ( o )
110     {
111         visit(o);
112         preorder(o->ch[0]);
113         preorder(o->ch[1]);
114     }
115 }
116 
117 /*
118 void inorder( Node * o )
119 {
120     if ( o )
121     {
122         inorder(o->ch[0]);
123         visit(o);
124         inorder(o->ch[1]);
125     }
126 }
127 
128 void postorder( Node * o )
129 {
130     if ( o )
131     {
132         postorder(o->ch[0]);
133         postorder(o->ch[1]);
134         visit(o);
135     }
136 }
137 */
138 
139 int main ()
140 {
141     while ( scanf("%d", &n) != EOF )
142     {
143         root = NULL;
144         cnt = 0;
145         for ( int i = 0; i < n; i++ )
146         {
147             int tmp;
148             scanf("%d", &tmp);
149             insert( root, tmp );
150         }
151         preorder(root);
152         free(root);        
153     }
154     return 0;
155 }