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| class Solution {
public boolean findTarget(TreeNode root, int k) {
Set<Integer> set = new HashSet<>();
return dfs(root, set, k);
}
private boolean dfs(TreeNode root, Set<Integer> set, int k) {
if (root == null) {
return false;
}
if (set.contains(k - root.val)) {
return true;
}
set.add(root.val);
return dfs(root.left, set, k) || dfs(root.right, set, k);
}
}
|
References
653. Two Sum IV - Input is a BST
剑指 Offer II 056. 二叉搜索树中两个节点之和