给一个排序数组(从小到大),将其转换为一棵高度最小的排序二叉树。
您在真实的面试中是否遇到过这个题?给出数组 [1,2,3,4,5,6,7]
, 返回
4
/ \
2 6
/ \ / \
1 3 5 7
可能有多个答案,返回任意一个即可
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/**
* Definition of TreeNode:
* public class TreeNode {
* public int val;
* public TreeNode left, right;
* public TreeNode(int val) {
* this.val = val;
* this.left = this.right = null;
* }
* }
*/
public class Solution {
/**
* @param A: an integer array
* @return: a tree node
*/
public TreeNode sortedArrayToBST(int[] A) {
// write your code here
if(A==null) return null;
TreeNode node = null;
node = CreateNode(node, A, 0, A.length-1);
return node;
}
public TreeNode CreateNode(TreeNode node, int[] A, int s, int e) {
if (s <= e) {
int mid = (s + e) / 2;
node = new TreeNode(A[mid]);
node.left = CreateNode(node, A, s, mid-1);
node.right = CreateNode(node, A, mid+1, e);
return node;
}
return null;
}
}