05 August 2008
给个树，找出其中大于等于low小于等于high的结点，全部加起来的值
随便一种遍历方式
Recursive
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/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode() {}
* TreeNode(int val) { this.val = val; }
* TreeNode(int val, TreeNode left, TreeNode right) {
* this.val = val;
* this.left = left;
* this.right = right;
* }
* }
*/
class Solution {
public int rangeSumBST(TreeNode root, int low, int high) {
int result = 0;
result += rangeSearch(root, low, high, result);
return result;
}
public int rangeSearch(TreeNode node, int low, int high, int result) {
if (node != null) {
if ((low <= node.val) && (node.val <= high))
result = result + node.val;
if (node.left != null)
result = rangeSearch(node.left, low, high, result);
if (node.right != null)
result = rangeSearch(node.right, low, high, result);
}
return result;
}
}
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class Solution {
int result = 0;
public int rangeSumBST(TreeNode root, int low, int high) {
if (root == null) {
return 0;
}
if (low > root.val) {
rangeSumBST(root.right, low, high);
} else if (high < root.val) {
rangeSumBST(root.left, low, high);
} else {
rangeSumBST(root.left, low, high);
rangeSumBST(root.right, low, high);
result += root.val;
}
return result;
}
}
Iterative
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