Title Description
Input binary tree root node, the tree determination is not a balanced binary tree. If the depth of a binary tree left any node in the right subtree differ by no more than 1, then it is a balanced binary tree. For example, in FIG binary tree is a balanced binary tree.
Ideas analysis
Determining a height difference between the left and right subtrees in depth during the binary tree, if the height difference is greater than 1, it returns -1, description is not a balanced binary tree, a binary tree of depth otherwise.
Test Case
- Functional test: balancing binary tree; not a balanced binary tree; all the nodes in the binary tree are no left / right subtree.
- Special input test: only one node in the binary tree; nullptr head node pointer of the binary tree.
Java code
public class Offer055_02 {
public static void main(String[] args) {
test1();
test2();
test3();
}
public static boolean IsBalanced_Solution(TreeNode root) {
return Solution1(root);
}
private static boolean Solution1(TreeNode root) {
return getDepth(root)!=-1;
}
private static int getDepth(TreeNode root) {
if(root==null) return 0;
int leftDep = getDepth(root.left);
if(leftDep == -1) return -1;
int rightDep = getDepth(root.right);
if(rightDep==-1) return -1;
return Math.abs(leftDep-rightDep) >1 ? -1 :(Math.max(leftDep,rightDep) + 1);
}
private static void test1() {
}
private static void test2() {
}
private static void test3() {
}
}