力扣递归之 543. 二叉树的直径
class Solution {
// 二叉树直径 其实就是根到左子树最深+根到右子树最深
int diameter;
public int diameterOfBinaryTree(TreeNode root) {
calculateDepth(root);
return diameter;
}
private int calculateDepth(TreeNode node) {
if (node == null) {
return 0;
}
int leftDepth = calculateDepth(node.left);
int rightDepth = calculateDepth(node.right);
diameter = Math.max(diameter, leftDepth + rightDepth);
return Math.max(leftDepth, rightDepth) + 1;
}
}