67 lines
1.6 KiB
Java
67 lines
1.6 KiB
Java
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//计算给定二叉树的所有左叶子之和。
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//
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// 示例：
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//
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//
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// 3
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// / \
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// 9 20
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// / \
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// 15 7
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//
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//在这个二叉树中，有两个左叶子，分别是 9 和 15，所以返回 24
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//
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//
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// Related Topics 树 深度优先搜索 广度优先搜索 二叉树
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// 👍 328 👎 0
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package leetcode.editor.cn;
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import com.code.leet.entiy.TreeNode;
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//404:左叶子之和
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class SumOfLeftLeaves {
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public static void main(String[] args) {
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//测试代码
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Solution solution = new SumOfLeftLeaves().new Solution();
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}
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//力扣代码
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//leetcode submit region begin(Prohibit modification and deletion)
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/**
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* Definition for a binary tree node.
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* public class TreeNode {
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* int val;
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* TreeNode left;
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* TreeNode right;
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* TreeNode() {}
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* TreeNode(int val) { this.val = val; }
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* TreeNode(int val, TreeNode left, TreeNode right) {
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* this.val = val;
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* this.left = left;
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* this.right = right;
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* }
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* }
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*/
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class Solution {
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public int sumOfLeftLeaves(TreeNode root) {
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if (root == null) {
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return 0;
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}
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int sum = 0;
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if (root.left != null) {
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if (root.left.left == null && root.left.right == null) {
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sum += root.left.val;
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}
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sum += sumOfLeftLeaves(root.left);
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}
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if (root.right != null) {
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sum += sumOfLeftLeaves(root.right);
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}
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return sum;
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}
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}
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//leetcode submit region end(Prohibit modification and deletion)
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}
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