Given a binary tree, you need to compute the length of the diameter of the tree. The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.
Example:
Given a binary tree
1 / \ 2 3 / \ 4 5
Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].
Note: The length of path between two nodes is represented by the number of edges between them.
二叉树的直径是指从一个叶节点到另一个叶节点的最远距离,而这个距离是指两个节点之间的路径长,注意,这条路径不一定经过根节点。
这里可以通过递归来完成计算,通过先递归的计算出左子树的最大高度,再递归的计算出右子树的最大高度,就可以得出当前节点可以构成的最长路径。需要将该值记录下来。再递归的返回该节点的最大高度给外层调用方运用。
int max = 0; public int diameterOfBinaryTree(TreeNode root) { heightOfBinaryTree(root); return max; } public int heightOfBinaryTree(TreeNode root) { if (root == null) { return 0; } int left = heightOfBinaryTree(root.left); int right = heightOfBinaryTree(root.right); max = Math.max(left + right + 1, max); return Math.max(left, right) + 1; }