[CareerCup][Google Interview] Find kth number in a BST

Find kth number in a BST

递归实现，按照左根右的顺序来实现

 1 #include <iostream>
 2 using namespace std;
 3 
 4 struct Node
 5 {
 6     Node *left;
 7     Node *right;
 8     int val;
 9     Node():left(NULL), right(NULL){}
10 };
11 
12 Node *findKthElement(Node *node, int &K)
13 {
14     if (node == NULL)
15         return NULL;
16 
17     Node *left = findKthElement(node->left, K);
18 
19     if (left != NULL)
20         return left;
21 
22     K--;
23 
24     if (K == 0)
25         return node;
26 
27     Node *right = findKthElement(node->right, K);
28 
29     return right;
30 }
31 
32 int main()
33 {
34     Node node[10];
35 
36     for(int i = 0; i < 10; i++)
37         node[i].val = i;
38 
39     node[4].left = &node[2];
40     node[4].right = &node[7];
41 
42     node[2].left = &node[1];
43     node[2].right = &node[3];
44 
45     node[1].left = &node[0];
46 
47     node[7].left = &node[6];
48     node[7].right = &node[8];
49 
50     node[6].left = &node[5];
51 
52     node[8].right = &node[9];
53 
54     for(int i = 1; i <= 10; i++)
55     {
56         int k = i;
57         Node *ret = findKthElement(&node[4], k);
58         cout << i << "th element:" << ret->val << endl;
59     }
60 }

 

 

posted @ 2012-11-05 11:42  chkkch  阅读(310)  评论(0)  编辑  收藏  举报