线索化二叉树
1 #include <stdio.h> 2 #include <stdlib.h> 3 #include <string.h> 4 #include <vector> 5 #include <stack> 6 #include <algorithm> 7 using namespace std; 8 9 typedef enum{ 10 Thread, 11 Link 12 }Tag; 13 14 typedef struct Node 15 { 16 int data; 17 struct Node * lchild; 18 struct Node * rchild; 19 Tag rtag; 20 Tag ltag; 21 } Node; 22 23 Node *createNode(int data, Node * l = NULL, Node * r = NULL) 24 { 25 Node * res = (Node *)malloc(sizeof(Node)); 26 res->data = data; 27 res->lchild = l; 28 res->rchild = r; 29 res->rtag = Link; 30 res->ltag = Link; 31 return res; 32 } 33 34 35 Node * createTree(Node * &root, int x) 36 { 37 if (root == NULL){ 38 root = createNode(x, NULL, NULL); 39 return root; 40 } 41 Node * p = root; 42 Node * q = NULL; 43 while(p != NULL){ 44 q = p; 45 if ( x > p->data ){ 46 p = p->rchild; 47 } 48 else { 49 p = p->lchild; 50 } 51 } 52 if ( x > q->data) q->rchild = createNode(x); 53 else q->lchild = createNode(x); 54 return root; 55 } 56 57 void print(Node * root) 58 { 59 if (root == NULL) return; 60 print(root->lchild); 61 printf("%d ", root->data); 62 print(root->rchild); 63 } 64 65 void mprint(Node * root) 66 { 67 Node * p = root; 68 stack<Node *> st; 69 st.push(root); 70 while (!st.empty()) { 71 if (st.top() == NULL) { 72 st.pop(); 73 if (!st.empty()) { 74 printf("%d ", st.top()->data); 75 Node * temp = st.top(); 76 st.pop(); 77 st.push(temp->rchild); 78 } 79 } 80 else { 81 st.push(st.top()->lchild); 82 } 83 } 84 } 85 86 void threadTree(Node *&prev, Node *root) { 87 if (root == NULL) return; 88 threadTree(prev, root->lchild); 89 if (root->lchild == NULL) { 90 root->lchild = prev; 91 root->ltag = Thread; 92 } 93 if (prev != NULL && prev->rchild == NULL) { 94 prev->rchild = root; 95 prev->rtag = Thread; 96 } 97 prev = root; 98 threadTree(prev, root->rchild); 99 } 100 101 102 int inThreadTreePrint(Node * root) { 103 Node * p = root; 104 while(p) { 105 if (p->lchild != NULL && p->ltag != Thread) 106 p = p->lchild; 107 else { 108 printf("%d ", p->data); 109 while (p->rchild != NULL && p->rtag == Thread) { 110 p = p->rchild; 111 printf("%d ", p->data); 112 } 113 p = p->rchild; 114 } 115 } 116 } 117 118 119 120 int main(void) 121 { 122 Node *root = NULL; 123 createTree(root, 5); 124 createTree(root, 4); 125 createTree(root, 9); 126 createTree(root, 7); 127 createTree(root, 1); 128 createTree(root, 2); 129 Node * prev = NULL; 130 threadTree(prev, root); 131 printf("%d ", root->lchild->data); 132 if (root->lchild->lchild) printf("%d ", root->lchild->lchild->data); 133 else printf("NULL "); 134 if (root->rchild->lchild->rchild) printf("%d ", root->rchild->lchild->rchild->data); 135 else printf("NULL "); 136 printf(" "); 137 printf("---------------------------------------------------- "); 138 inThreadTreePrint(root); 139 return 0; 140 }