二叉查找树

  1 #include "stdafx.h"
  2 /* ZQU OJ 1377 二叉查找树 */
  3 #include <iostream>
  4 #include <cstdlib>
  5 #include <string>
  6 #include <cstring>
  7 #include <stack>
  8 bool FLAG = false;
  9 using namespace std;
 10 typedef int key_type;
 11 typedef struct SerachTree {
 12     key_type key;
 13     struct SerachTree *LChild, *RChild;
 14 }SerachTree, *PNode;
 15 
 16 void INSERT(key_type insert_num, PNode *root) {
 17     //初始化一个临时节点
 18     PNode tmp = (PNode)malloc(sizeof(SerachTree));
 19     tmp->key = insert_num;
 20     tmp->LChild = tmp->RChild = NULL;
 21     //当为空树时
 22     if ((*root) == NULL) {
 23         *root = tmp;
 24         return;
 25     }
 26     //树非空
 27     else {
 28         if (insert_num < (*root)->key)   //递归，以左儿子做新的根节点
 29             INSERT(insert_num, &(*root)->LChild);
 30         if (insert_num >(*root)->key)  //递归，以右儿子做新的根节点
 31             INSERT(insert_num, &(*root)->RChild);
 32     }
 33     return;
 34 }
 35 PNode FIND(key_type find_num, PNode point) {
 36     //PNode res = NULL;
 37     //cout << "point:" << endl;
 38     // cout << point->key << ‘ ‘ << (point->LChild) << ‘ ‘ << point->RChild <<endl;
 39     //point = (PNode)malloc(sizeof(SerachTree));   //不能再分配内存（传入一个地址，这个地址指向已有的结构体，不需要开新内存）
 40     //cout << "@" << endl;
 41     if (point == NULL)
 42         return NULL;
 43     if (find_num == point->key) {
 44         //cout << "point->key=" << point->key << " point->LChild=" << point->LChild << " point->RChild=" << point->RChild <<endl;
 45         return point;
 46     }
 47     else {
 48         //往左边走
 49         if (find_num < point->key && point->LChild != NULL)
 50             FIND(find_num, point->LChild);
 51         else if (find_num > point->key && point->RChild != NULL)
 52             FIND(find_num, point->RChild);
 53         else return NULL;
 54     }
 55 
 56     //return res;
 57 }
 58 //遍历二叉树，中序
 59 void TRAVERSE(PNode N) {
 60     //如果该树为空
 61     //cout << "N->key=" << N->key <<endl;
 62     //N = (PNode)malloc(sizeof(SerachTree) );
 63     // cout << N->LChild << ‘ ‘ << N->RChild << endl;
 64     //FLAG = false;
 65     if (N != NULL) {
 66         //if(N->LChild != NULL)
 67         FLAG = true;
 68         TRAVERSE(N->LChild);
 69         // else return;
 70         cout << N->key << ‘ ‘;
 71         //if(N->RChild != NULL)
 72         TRAVERSE(N->RChild);
 73         //else return;
 74     }
 75     else return;
 76 }
 77 PNode FindMin(PNode T) {
 78     if (T == NULL)
 79         return NULL;
 80     if (T->LChild == NULL)
 81         return T;
 82     else
 83         FindMin(T->LChild);
 84 }
 85 void DELETE(key_type delete_num, PNode *N) {
 86     PNode TmpCell;
 87     TmpCell = (PNode)malloc(sizeof(SerachTree));
 88     //空树
 89     if ((*N) == NULL)
 90         return;
 91     else if (delete_num < (*N)->key) {
 92         DELETE(delete_num, &(*N)->LChild);
 93     }
 94     else if (delete_num >(*N)->key) {
 95         DELETE(delete_num, &(*N)->RChild);
 96     }
 97     //两个儿子
 98     else if ((*N)->LChild && (*N)->RChild) {
 99         TmpCell = FindMin((*N)->RChild);
100         (*N)->key = TmpCell->key;
101         DELETE((*N)->key, &(*N)->RChild);
102     }
103     //一个儿子||叶节点
104     else {
105         TmpCell = *N;
106         if ((*N)->LChild == NULL/* && (*N)->RChild != NULL*/)
107             *N = (*N)->RChild;
108         else if ((*N)->RChild == NULL/* && (*N)->LChild != NULL*/)
109             (*N) = (*N)->LChild;
110         //cout << TmpCell->key << ‘ ‘ << TmpCell->LChild << ‘ ‘ << TmpCell->RChild << endl;
111         //删除节点
112         //cout << "N =" << N << endl;
113         free(TmpCell);
114         //(*N )= NULL;
115         TmpCell = NULL;
116         //*N = NULL;
117         //N = NULL;
118         //cout << TmpCell->key << ‘ ‘ << TmpCell->LChild << ‘ ‘ << TmpCell->RChild << endl;
119         //cout << (*N)->key << ‘ ‘ << (*N)->LChild << ‘ ‘ << (*N)->RChild << endl;
120         return;
121     }
122 
123 }
124 int main()
125 {
126     string command;
127     int command_num;
128     PNode Root;
129     Root = (SerachTree*)malloc(sizeof(SerachTree));
130     Root = NULL;
131     //Root->LChild = Root->RChild = NULL;
132     while (cin >> command) {
133         //getchar();
134         if (command != "traverse") {
135             //cout << ‘!‘;
136             cin >> command_num;
137             //cout << command << endl;
138             if (command == "insert")
139                 INSERT(command_num, &Root);
140             //cout <<Root;
141             if (command == "find") {
142                 string find_res[2] = { "yes", "no" };
143                 if (FIND(command_num, Root) != NULL) {
144                     cout << find_res[0] << endl;
145                 }
146                 else cout << find_res[1] << endl;
147             }
148             if (command == "delete") {
149                 DELETE(command_num, &Root);
150             }
151         }
152         else if (command == "traverse") {
153             //cout << command <<endl;
154             FLAG = false;
155             TRAVERSE(Root);
156             if (FLAG)
157                 cout << endl;
158         }
159     }
160 }