6308. 二叉树中的第 K 大层和

Author: w2xi

README.md

@@ -243,6 +243,7 @@
 |2341|[数组能形成多少数对](https://leetcode.cn/problems/maximum-number-of-pairs-in-array/)|[JavaScript](./algorithms/maximum-number-of-pairs-in-array.js)|Easy|
 |2351|[第一个出现两次的字母](https://leetcode.cn/problems/first-letter-to-appear-twice/)|[JavaScript](./algorithms/first-letter-to-appear-twice.js)|Easy|
 |2357|[使数组中所有元素都等于零](https://leetcode.cn/problems/make-array-zero-by-subtracting-equal-amounts/)|[JavaScript](./algorithms/make-array-zero-by-subtracting-equal-amounts.js)|Easy|
+|6308|[二叉树中的第 K 大层和](https://leetcode.cn/problems/kth-largest-sum-in-a-binary-tree/)|[JavaScript](./algorithms/kth-largest-sum-in-a-binary-tree.js)|Medium|
 |6354|[找出数组的串联值](https://leetcode.cn/problems/find-the-array-concatenation-value/)|[JavaScript](./algorithms/find-the-array-concatenation-value.js)|Easy|
 |6362|[合并两个二维数组 - 求和法](https://leetcode.cn/problems/merge-two-2d-arrays-by-summing-values/)|[JavaScript](./algorithms/merge-two-2d-arrays-by-summing-values.js)|Easy|
 |6367|[求出最多标记下标](https://leetcode.cn/problems/find-the-maximum-number-of-marked-indices/)|[JavaScript](./algorithms/find-the-maximum-number-of-marked-indices.js)|Medium|

algorithms/kth-largest-sum-in-a-binary-tree.js

@@ -0,0 +1,37 @@
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * 6308. 二叉树中的第 K 大层和
+ * @param {TreeNode} root
+ * @param {number} k
+ * @return {number}
+ */
+var kthLargestLevelSum = function (root, k) {
+  // BFS
+  let depth = 0;
+  const queue = [root];
+  let result = [];
+
+  while (queue.length) {
+    let size = queue.length;
+    let sum = 0;
+    while (size--) {
+      const node = queue.shift();
+      sum += node.val;
+      node.left && queue.push(node.left);
+      node.right && queue.push(node.right);
+    }
+    result.push(sum);
+    depth++;
+  }
+  if (k > depth) return -1;
+  result.sort((a, b) => b - a);
+
+  return result[k - 1] ? result[k - 1] : -1;
+};