二叉树的遍历

1 struct node {
2     int value;
3     struct node* lson;
4     struct node* rson;
5 };
6 typedef struct node* tree;

 

先序遍历：根结点 -> 左子树 -> 右子树

 

1 void PreorderTraversal(tree root) {
2     if(root) {
3         printf("%d ", root->value);
4         PreorderTraversal(root->lson);
5         PreorderTraversal(root->rson);
6     }
7 }

先序遍历

 

 

中序遍历：左子树 -> 根结点 -> 右子树

1 void InorderTraversal(tree root) {
2     if(root) {
3         InorderTraversal(root->lson);
4         printf("%d ", root->value);
5         InorderTraversal(root->rson);
6     }
7 }

中序遍历

 

后序遍历：左子树 -> 右子树 -> 根结点

1 void PostorderTraversal(tree root) {
2     if(root) {
3         PostorderTraversal(root->lson);
4         PostorderTraversal(root->rson);
5         printf("%d ", root->value);
6     }
7 }

后序遍历

 

层序遍历：

 1 #define maxSize 100050
 2 void LevelordetTraversal(tree root) {
 3     if (root == NULL) {
 4         return ;
 5     }
 6 
 7     struct node queue[maxSize] = {0};
 8     int head = 0, tail = 1;
 9     queue[head] = (*root);
10 
11     while (head < tail) {
12         printf("%d", queue[head].value);
13 
14         if (queue[head].lson) {
15             queue[tail++] = (*queue[head].lson);
16         }
17         if (queue[head].rson) {
18             queue[tail++] = (*queue[head].rson);
19         }
20 
21         ++head;
22     }
23 }

层序遍历