二叉树（含有duplicates字段来实现懒惰删除，还有完全删除节点)

 

#include <stdio.h>
#include <malloc.h>
#include <time.h>
#include <stdlib.h>
typedef struct BiTree
...{
    int value;
    int duplicates;
    struct BiTree *left,*right;
}BiTree;
BiTree* CreateBiTree()/**//**//**//*return dummy root */
...{
    BiTree *node=(BiTree*)malloc(sizeof(BiTree));
    node->left=NULL;
    node->right=NULL;
    return node;
}
int SearchNode(BiTree *root,BiTree **parent,BiTree **node,int x)
/**//**//**//*if exist return 1,else return 0*/
/**//**//**//*parent:return the parent of the node with value of x*/
...{
    BiTree *p1;/**//**//**//*used as node*/
    BiTree *p2/**//**//**//*used as parent node*/;
    p1=root->left,p2=root;
    while(p1!=NULL)
    ...{
        if(x==p1->value)
        ...{
            *node=p1;/**//**//**//*motify the node and parent*/
            *parent=p2;
            return 1;
        }
        else if(x<p1->value)
        ...{
            p2=p1;
            p1=p1->left;
        }
        else if(x>p1->value)
        ...{
            p2=p1;
            p1=p1->right;
        }
    }
    *node=p1;/**//**//**//*motify the node and parent*/
    *parent=p2;
    return 0;
}
int InsertNode(BiTree *root,int x)
...{
/**//**//**//*if x exist in BiTree ,return 0*/
/**//**//**//*else return 1;*/
    BiTree *parent=NULL,*node=NULL;
    if(SearchNode(root,&parent,&node,x)==1)/**//**//**//*if x eixst in Bitree */
    /**//**//**//*duplicates++*/
    ...{
        node->duplicates++;
        return 0;
    }
    else
    ...{
        node=(BiTree*)malloc(sizeof(BiTree));
        node->value=x;
        node->duplicates=1;
        node->left=NULL;
        node->right=NULL;
        if(parent==root)
            root->left=node;
        else if(x<parent->value)
            parent->left=node;
        else if(x>parent->value)
            parent->right=node;
        return 1;
    }
}
void FreeBiTree(BiTree* root)
...{
    BiTree *left=NULL,*right=NULL;
    if(root!=NULL)
    ...{
        left=root->left;
        right=root->right;
        free(root);
        FreeBiTree(left);
        FreeBiTree(right);
    }
}
int DeleteNode(BiTree *root,int x)
...{
/**//**//**//*if x exist in BiTree ,return 1*/
/**//**//**//*else return 0;*/
    BiTree *node=NULL,*parent=NULL;
    BiTree *p1=NULL,*p2=NULL;
    int result;
    result=SearchNode(root,&parent,&node,x);
    if(result==0)
        return 0;/**//**//**//*x doesn't exist in the BiTree */
    else
    ...{
        if(node->duplicates>1)
        ...{
            printf("Duplicate>1 ");
              node->duplicates--;/**//**//**//*lazy delete*/
        }          
        else/**//**//**//*delete node which duplicates is zero*/
        ...{
            if((node->left==NULL)&&(node->right==NULL))
            ...{
                if(node==parent->left)
                    parent->left=NULL;
                else if(node==parent->right)
                    parent->right=NULL;
                free(node);
            } 
            else if((node->left!=NULL)&&(node->right!=NULL))
            ...{
                p1=node;
                p2=node->right;
                if(p2->left==NULL)
                ...{
                    p1->value=p2->value;
                    p1->duplicates=p2->duplicates;
                    p1->right=p2->right;
                    free(p2);
                }
                else
                ...{
                    while(p2->left!=NULL)
                    ...{
                        p1=p2;
                        p2=p2->left;
                    }
                    node->value=p2->value;
                    node->duplicates=p2->duplicates;
                    p1->left=p2->right;
                    free(p2);
                }
            }
            else if(node->left!=NULL)
            ...{
                if(parent->left==node)
                    parent->left=node->left;
                else if(parent->right==node)
                    parent->right=node->left;
                free(node);
            }
            else if(node->right!=NULL)
            ...{
                if(parent->left==node)
                    parent->left=node->right;
                else if(parent->right==node)
                    parent->right=node->right;
                free(node);
            }
        }
        return 1;
    }
}
void Traverse(BiTree *root,int depth)
...{
    int i;
    if(root==NULL)
        return ;
    else
    ...{
        Traverse(root->left,depth+1);
        for(i=0;i<depth;i++)
            putchar('*');
        printf("%d ",root->value);
        Traverse(root->right,depth+1);
        return ;
    }
}
int main()
...{
    int i,size=100,x;
    BiTree *root;
    srand((unsigned)time(NULL));
    root=CreateBiTree();
    for(i=0;i<size;i++)
    ...{
        x=rand();
        InsertNode(root,x);        
    }
    Traverse(root->left,0);
    while(x!=0)
    ...{
        scanf("%d",&x);
        DeleteNode(root,x);
        printf("After DeleteNode ");
        Traverse(root->left,0);
    }
    FreeBiTree(root);/**//**//**//*because is't dummy*/
    return 0;
}