继上一篇《思考红黑树》 自己亲自动手把红黑树实现一遍,发现理论成功了要转换为实际代码还是有点难度的,困难点主要在于一些边界点的确定。花了两小时才把所有的东西调通,还是需要进一步提高自己的C功力。
直接贴代码吧,有需要的拿去用,我自己也留着以后拿来玩玩。
这份代码肯定是需要根据实际环境进行修改的,前两天大概扫了一下 《Linux内核中的红黑树》里面的代码,发现自己写的代码水平跟大神写的还是有些差距啊...加油吧。
//rb_tree.h
#include <stdio.h> #include <stdlib.h> #ifndef RB_TREE #define RB_TREE typedef struct{int value;}rbtree_key; typedef struct{int value;}rbtree_data; typedef enum rbtree_color{RB_RED,RB_BLACK}rbtree_color; int rbtree_key_cmp(rbtree_key x,rbtree_key y); typedef struct rbtree_node rbtree_node; //rb tree node struct rbtree_node{ rbtree_key key; rbtree_color color; rbtree_data data; rbtree_node *parent; rbtree_node *left; rbtree_node *right; }; rbtree_node * rb_nil; static int rb_nil_inited; void rbtree_init_nil(); void rbtree_destroy_nil(); void rbtree_node_cpy(rbtree_node *source,rbtree_node *dest); rbtree_node * rbtree_search(rbtree_node * t,rbtree_key key); rbtree_node * rbtree_search_iterative(rbtree_node * t,rbtree_key key); rbtree_node * rbtree_min(rbtree_node *t); rbtree_node * rbtree_max(rbtree_node *t); rbtree_node * rbtree_successor(rbtree_node *t); rbtree_node * rbtree_predecessor(rbtree_node *t); void rbtree_insert(rbtree_node **root,rbtree_node *z); void rbtree_insert_fixup(rbtree_node **root,rbtree_node *z); void rbtree_delete(rbtree_node **root,rbtree_node *z); void rbtree_delete_fixup(rbtree_node **root,rbtree_node *z); void rbtree_left_roate(rbtree_node **root,rbtree_node *z); void rbtree_right_roate(rbtree_node **root,rbtree_node *z); #endif
rb_tree.c
#include "rb_tree.h" int rbtree_key_cmp(rbtree_key x,rbtree_key y){ return y.value-x.value; } void rbtree_node_cpy(rbtree_node *source,rbtree_node *dest){ dest->key.value = source->key.value; dest->data.value = source->data.value; } void rbtree_init_nil(){ if(!rb_nil_inited){ rb_nil = (rbtree_node *)malloc(sizeof(rbtree_node)); rb_nil->color = RB_BLACK; rb_nil->parent = rb_nil; rb_nil->left = rb_nil; rb_nil->right = rb_nil; rb_nil_inited = 1; } } void rbtree_destroy_nil(){ if(rb_nil_inited){ free(rb_nil); rb_nil=NULL; rb_nil_inited = 0; } } rbtree_node * rbtree_search(rbtree_node * t,rbtree_key key){ int cmp = rbtree_key_cmp(t->key,key); if(rb_nil == t || 0 == cmp ) return t; return cmp<0?rbtree_search(t->left,key):rbtree_search(t->right,key); } rbtree_node * rbtree_search_iterative(rbtree_node * t,rbtree_key key){ int cmp = rbtree_key_cmp(t->key,key); while(rb_nil != t && 0!=cmp){ t = cmp<0?t->left:t->right; } return t; } rbtree_node * rbtree_min(rbtree_node *t){ while(rb_nil != t->left){ t = t->left; } return t; } rbtree_node * rbtree_max(rbtree_node *t){ while(rb_nil != t->right){ t = t->right; } return t; } rbtree_node * rbtree_successor(rbtree_node *t){ rbtree_node * parent; if(rb_nil != t->right){ return rbtree_min(t->right); } parent = t->parent; while(parent != rb_nil && t == parent->right){ t = parent; parent = parent->parent; } return parent; } rbtree_node * rbtree_predecessor(rbtree_node *t){ rbtree_node * parent; if(rb_nil != t->left){ return rbtree_max(t->left); } parent = t->parent; while(rb_nil != parent && t == parent->left ){ t = parent; parent = parent->parent; } return parent; } void rbtree_insert(rbtree_node **root,rbtree_node *z){ int cmp; rbtree_node *p,*t; if(rb_nil == *root){ *root = z; return; } t = *root; while( rb_nil != t){ p = t; cmp = rbtree_key_cmp(t->key,z->key); t = cmp<0?t->left:t->right; } if(cmp<0){ p->left = z; }else{ p->right = z; } z->parent = p; z->color = RB_RED; if(z->parent->color == RB_RED){ rbtree_insert_fixup(root,z); } } void rbtree_insert_fixup(rbtree_node **root,rbtree_node *z){ while(z->parent->color == RB_RED){ if(z->parent == z->parent->parent->left){ //case 1 if(z->parent->parent->right->color == RB_RED){ z->parent->parent->color = RB_RED; z->parent->parent->left->color = RB_BLACK; z->parent->parent->right->color = RB_BLACK; z = z->parent->parent; }else{ //case2 if(z == z->parent->right){ z = z->parent; rbtree_left_roate(root,z); } //case3 z->parent->color = RB_BLACK; z->parent->parent->color = RB_RED; rbtree_right_roate(root,z->parent->parent); } }else{ //case 1 if(z->parent->parent->left->color == RB_RED){ z->parent->parent->color = RB_RED; z->parent->parent->left->color = RB_BLACK; z->parent->parent->right->color = RB_BLACK; z = z->parent->parent; }else{ //case2 if(z == z->parent->left){ z = z->parent; rbtree_right_roate(root,z); } //case3 z->parent->color = RB_BLACK; z->parent->parent->color = RB_RED; rbtree_left_roate(root,z->parent->parent); } } } (*root)->color = RB_BLACK; } void rbtree_delete(rbtree_node **root,rbtree_node *z){ rbtree_node *parent; rbtree_node *inherit; rbtree_node *delete; //find which node to delete if(z->left != rb_nil && z->right != rb_nil){ delete = rbtree_successor(z); rbtree_node_cpy(delete,z); }else{ delete = z; } //find the inherit node of the delete node if(delete->left != rb_nil){ inherit = delete->left; }else{ inherit = delete->right; } //connect inherit to delete node's parent parent = delete->parent; inherit->parent = parent; //connect delete node's parent to inherit if(parent == rb_nil){ *root = inherit; }else{ if(delete == parent->left){ parent->left = inherit; }else{ parent->right = inherit; } } if(delete->color = RB_BLACK){ rbtree_delete_fixup(root,inherit); } free(delete); return; } void rbtree_delete_fixup(rbtree_node **root,rbtree_node *z){ while(z != *root && z->color == RB_BLACK){ if(z == z->parent->left){ //case1 if(z->parent->right->color == RB_RED){ z->parent->color = RB_RED; z->parent->right->color = RB_BLACK; rbtree_left_roate(root,z->parent); }else{ //case2 if(z->parent->right->left->color == RB_BLACK && z->parent->right->right->color == RB_BLACK){ z->parent->right->color = RB_RED; z = z->parent; }else{ //case3 if(z->parent->right->left->color == RB_RED){ z->parent->right->left->color = RB_BLACK; z->parent->right->color = RB_RED; rbtree_right_roate(root,z->parent->right); } //case4 z->parent->right->color = z->parent->color; z->parent->right->right->color = RB_BLACK; z->parent->color = RB_BLACK; rbtree_left_roate(root,z->parent); break; } } }else{ //case1 if(z->parent->left->color == RB_RED){ z->parent->color = RB_RED; z->parent->left->color = RB_BLACK; rbtree_right_roate(root,z->parent); }else{ //case2 if(z->parent->left->left->color == RB_BLACK && z->parent->left->right->color == RB_BLACK){ z->parent->left->color = RB_RED; z = z->parent; }else{ //case3 if(z->parent->left->right->color == RB_RED){ z->parent->left->right->color = RB_BLACK; z->parent->left->color = RB_RED; rbtree_left_roate(root,z->parent->left); } //case4 z->parent->left->color = z->parent->color; z->parent->left->left->color = RB_BLACK; z->parent->color = RB_BLACK; rbtree_right_roate(root,z->parent); break; } } } } z->color = RB_BLACK; } //assume that z's right child is not rb_nil void rbtree_left_roate(rbtree_node **root,rbtree_node *z){ rbtree_node *right_child; right_child = z->right; //1. z->right = right_child->left; if(right_child->left != rb_nil){ right_child->left->parent = z; } //2. right_child->left = z; right_child->parent = z->parent; if(right_child->parent == rb_nil){ *root = right_child; //3. }else if(z == z->parent->left){ z->parent->left = right_child; }else{ z->parent->right = right_child; } z->parent = right_child; } //assume that z's left child is not rb_nil void rbtree_right_roate(rbtree_node **root,rbtree_node *z){ rbtree_node *left_child; left_child = z->left; //1. z->left = left_child->right; if(left_child->right != rb_nil){ left_child->right->parent = z; } //2. left_child->right = z; left_child->parent = z->parent; if(left_child->parent == rb_nil){ *root = left_child; //3. }else if(z == z->parent->left){ z->parent->left = left_child; }else{ z->parent->right = left_child; } z->parent = left_child; }
//测试代码 t.c
#include <stdio.h> #include <stdlib.h> #include "lib/rb_tree.h" rbtree_node * rbtree_create(int num); rbtree_node * rbtree_add(rbtree_node **root,int num); void rbtree_destroy(rbtree_node *t); void rbtree_print(rbtree_node * t); rbtree_node * rbtree_find(rbtree_node *t,int num); int main(int argc,char *argv[]){ rbtree_node *t,*p,*max,*min; int arr[] = {9,8,11,18,2,5,16,1,8}; int i; rbtree_init_nil(); t = rbtree_create(10); t->color = RB_BLACK; for(i=0;i<9;i++){ rbtree_add(&t,arr[i]); rbtree_print(t); printf("================= "); } p = rbtree_min(t); printf("%d:%p p:%p,l:%p,r:%p ",p->key.value,p,p->parent,p->left,p->right); while((p=rbtree_successor(p)) != rb_nil){ printf("%d:%p p:%p,l:%p,r:%p ",p->key.value,p,p->parent,p->left,p->right); } printf(" "); min = rbtree_min(t); printf("t:%p,min:%p ",t,min); do{ printf("-------------- "); rbtree_print(t); max = rbtree_max(t); printf("%d ",max->key.value); p = max; while((p=rbtree_predecessor(p))!=rb_nil){ printf("%d ",p->key.value); } printf(" "); rbtree_delete(&t,max); }while(t!=rb_nil); printf(" t:%p ",t); rbtree_destroy(t); rbtree_destroy_nil(); return 0; } rbtree_node * rbtree_create(int num){ rbtree_node *p; p = (rbtree_node *)malloc(sizeof(rbtree_node)); p->key.value = num; p->data.value = 0; p->color = RB_RED; p->left = rb_nil; p->right = rb_nil; p->parent = rb_nil; return p; } rbtree_node * rbtree_add(rbtree_node **root,int num){ rbtree_node *p; p = rbtree_create(num); rbtree_insert(root,p); } rbtree_node * rbtree_find(rbtree_node *t,int num){ rbtree_key key; key.value = num; return rbtree_search(t,key); } void rbtree_destroy(rbtree_node *t){ if(rb_nil == t) return; rbtree_node *p; p = t; free(t); if(p->left) rbtree_destroy(p->left); if(p->right) rbtree_destroy(p->right); } void rbtree_print(rbtree_node * t){ if(rb_nil == t) return; printf(" %d-%d ",t->key.value,t->color); printf(" ↙"); printf(" ↘ "); if(t->left != rb_nil){ printf(" %d-%d",t->left->key.value,t->left->color); }else{ printf(" nil-%d",t->left->color); } if(t->right != rb_nil){ printf(" %d-%d",t->right->key.value,t->right->color); }else{ printf(" nil-%d",t->right->color); } printf(" "); rbtree_print(t->left); rbtree_print(t->right); }