[leetcode]Lowest Common Ancestor of a Binary Tree

这题仔细点把base case写好就好了。

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public class Solution { TreeNode result = null; public TreeNode lowestCommonAncestor(TreeNode root, TreeNode p, TreeNode q) { findResult(root, p, q, new boolean[2]); return result; } private void findResult(TreeNode root, TreeNode p, TreeNode q, boolean[]p_q){ if (root == null) return; boolean forLeft[] = new boolean[2]; boolean forRight[] = new boolean[2]; if (result == null) findResult (root.left, p, q, forLeft); if (result == null) findResult (root.right, p, q, forRight); p_q[0] |= (root == p) || forLeft[0] || forRight[0]; p_q[1] |= (root == q) || forRight[1] || forLeft[1]; if (p_q[0] && p_q[1] && result == null) result = root; return; } }