/******* avl.h **********/
1 /***********************************************************/ 2 /* Copyright (C) SA14226214, USTC, 2014-2015 */ 3 /* */ 4 /* FILE NAME : avl.h */ 5 /* PRINCIPAL AUTHOR : GaoZhipeng */ 6 /* SUBSYSTEM NAME : AVL_Tree */ 7 /* MODULE NAME : AVL_Tree */ 8 /* LANGUAGE : C */ 9 /* TARGET ENVIRONMENT : ANY */ 10 /* DATE OF FIRST RELEASE : 2015/05/09 */ 11 /* DESCRIPTION : This is a bst_tree program */ 12 /***********************************************************/ 13 14 /* 15 *Revision log: 16 * 17 *Ceated by GaoZhipeng, 2015/05/09 18 * 19 */ 20 21 #ifndef _AVL_TREE_H 22 #define _AVL_TREE_H 23 24 #define ElementType int 25 26 struct AvlNode; 27 typedef struct AvlNode *Position; 28 typedef struct AvlNode *AvlTree; 29 30 31 AvlTree MakeEmpty( AvlTree T ); 32 Position Find( ElementType X, AvlTree T ); 33 Position FindMin( AvlTree T ); 34 Position FindMax( AvlTree T ); 35 AvlTree Insert( ElementType X, AvlTree T ); 36 //AvlTree Delete( ElementType X, AvlTree T ); 37 //ElementType Retrieve( Position P ); 38 39 static Position SingleRotateWithLeft( Position K2 ); 40 static Position SingleRotateWithRight( Position K1 ); 41 static Position DoubleRotateWithLeft( Position K3 ); 42 static Position DoubleRotateWithRight( Position K1 ); 43 44 45 #endif
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/******** avl.c **********/
1 /***********************************************************/ 2 /* Copyright (C) SA14226214, USTC, 2014-2015 */ 3 /* */ 4 /* FILE NAME : avl.c */ 5 /* PRINCIPAL AUTHOR : GaoZhipeng */ 6 /* SUBSYSTEM NAME : AVL_Tree */ 7 /* MODULE NAME : AVL_Tree */ 8 /* LANGUAGE : C */ 9 /* TARGET ENVIRONMENT : ANY */ 10 /* DATE OF FIRST RELEASE : 2015/05/09 */ 11 /* DESCRIPTION : This is a bst_tree program */ 12 /***********************************************************/ 13 14 /* 15 *Revision log: 16 * 17 *Ceated by GaoZhipeng, 2015/05/09 18 * 19 */ 20 21 #include<stdio.h> 22 #include<malloc.h> 23 #include"avl.h" 24 25 struct AvlNode 26 { 27 ElementType Element; 28 AvlTree Left; 29 AvlTree Right; 30 int Height; 31 }; 32 33 static int 34 Height( Position P ) 35 { 36 if(P == NULL) 37 { 38 return -1; 39 } 40 else return P->Height; 41 } 42 43 44 AvlTree MakeEmpty( AvlTree T ) 45 { 46 if(T != NULL) 47 { 48 MakeEmpty(T->Left); 49 MakeEmpty(T->Right); 50 free(T); 51 } 52 return NULL; 53 } 54 55 56 Position 57 Find( ElementType X, AvlTree T ) 58 { 59 if(T == NULL) 60 { 61 return NULL; 62 } 63 if(T->Element < X) 64 { 65 Find(X, T->Left); 66 } 67 else if(T->Element > X) 68 { 69 Find(X, T->Right); 70 } 71 else return T; 72 } 73 74 75 Position 76 FindMin( AvlTree T ) 77 { 78 if(T == NULL) 79 { 80 return NULL; 81 } 82 else 83 { 84 if(T->Left == NULL) 85 { 86 return T; 87 } 88 else 89 { 90 FindMin( T->Left ); 91 } 92 } 93 } 94 95 Position 96 FindMax( AvlTree T) 97 { 98 if(T == NULL) 99 { 100 return NULL; 101 } 102 else 103 { 104 if(T->Right == NULL) 105 { 106 return T; 107 } 108 else 109 { 110 FindMax(T->Right); 111 } 112 } 113 } 114 115 116 AvlTree 117 Insert( ElementType X, AvlTree T ) 118 { 119 if(T == NULL) 120 { 121 T = malloc( sizeof(struct AvlNode) ); 122 if(T == NULL) 123 { 124 printf("Out of space!!!"); 125 } 126 else 127 { 128 T->Element = X; 129 T->Height = 0; 130 T->Left = T->Right = NULL; 131 } 132 } 133 else if (X < T->Element) 134 { 135 T->Left = Insert(X, T->Left); 136 if( Height(T->Left) - Height(T->Right) == 2 ) 137 { 138 if( X < T->Left->Element ) 139 { 140 T = SingleRotateWithLeft(T); 141 } 142 else 143 { 144 T = DoubleRotateWithLeft(T); 145 } 146 } 147 } 148 else if (X > T->Element) 149 { 150 T->Right = Insert(X, T->Right); 151 if( Height(T->Right) - Height(T->Left) == 2) 152 { 153 if(X > T->Right->Element) 154 { 155 T = SingleRotateWithRight(T); 156 } 157 else 158 { 159 T = DoubleRotateWithRight(T); 160 } 161 } 162 } 163 164 T->Height = Max(Height(T->Left), Height(T->Right)) + 1; 165 return T; 166 } 167 168 static Position 169 SingleRotateWithLeft( Position K2 ) 170 { 171 Position K1; 172 173 K1 = K2->Left; 174 K2->Left = K1->Right; 175 K1->Right = K2; 176 177 K2->Height = Max( Height(K2->Left), Height(K2->Right) ) + 1; 178 K1->Height = Max( Height(K1->Left), Height(K1->Left) ) + 1; 179 return K1; 180 } 181 182 static Position 183 SingleRotateWithRight( Position K1 ) 184 { 185 Position K2; 186 187 K2 = K1->Right; 188 K1->Left = K2->Right; 189 K2->Right = K1; 190 191 K1->Height = Max( Height(K1->Left), Height(K1->Right) ) + 1; 192 K2->Height = Max( Height(K2->Left), Height(K2->Right) ) + 1; 193 194 return K2; 195 } 196 197 198 static Position 199 DoubleRotateWithLeft(Position K3) 200 { 201 Position K1; 202 203 K1 = K3->Left; 204 K3->Left = SingleRotateWithRight( K1 ); 205 206 return SingleRotateWithLeft(K3); 207 } 208 209 static Position 210 DoubleRotateWithRight(Position K1) 211 { 212 Position K3; 213 214 K3 = K1->Right; 215 K1->Right = SingleRotateWithLeft(K3); 216 217 return SingleRotateWithRight(K1); 218 } 219 220 int Max( int H1, int H2 ) 221 { 222 return H1>H2 ? : H1, H2; 223 }
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