作者:阿悅11 | 来源:互联网 | 2023-09-25 10:31
404. Sum of Left Leaves
Find the sum of all left leaves in a given binary tree.
Example:
3
/ \
9 20
/ \
15 7
There are two left leaves in the binary tree, with values 9 and 15 respectively. Return 24.
求所有的左叶子节点的和
java代码:
/**
* Definition for a binary tree node.
* public class TreeNode {
* int val;
* TreeNode left;
* TreeNode right;
* TreeNode(int x) { val = x; }
* }
*/
public class Solution {
private void searchBT(TreeNode root, int[] sum){
if(root.left!=null){
if(root.left.left==null&&root.left.right==null)sum[0]+=root.left.val;
}
if(root.left!=null)searchBT(root.left,sum);
if(root.right!=null)searchBT(root.right,sum);
}
public int sumOfLeftLeaves(TreeNode root) {
int[] sum={0};////要是调用函数时改变sum的值,只有将其声明为对象,所以这里将其声明为int[]
if(root!=null)searchBT(root,sum);
return sum[0];
}
}