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+---
+layout: post
+title: " LeetCode : 1161. Maximum Level Sum of a Binary Tree "
+categories: LeetCode
+author: goodGid
+use_math: true
+---
+* content
+{:toc}
+
+## [1161. Maximum Level Sum of a Binary Tree](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree)
+
+### Problem
+
+```
+Given the root of a binary tree, the level of its root is 1, the level of its children is 2, and so on.
+Return the smallest level x such that the sum of all the values of nodes at level x is maximal.
+```
+
+
+---
+
+### Example
+
+```
+Input: root = [1,7,0,7,-8,null,null]
+Output: 2
+Explanation: 
+Level 1 sum = 1.
+Level 2 sum = 7 + 0 = 7.
+Level 3 sum = 7 + -8 = -1.
+So we return the level with the maximum sum which is level 2.
+```
+
+---
+
+### [1] Code (23. 08. 20) (x)
+
+``` java
+// Runtime: 8 ms
+// Memory Usage: 46.2 MB
+// Ref : https://leetcode.com/submissions/detail/1026676455
+class Solution {
+    public int maxLevelSum(TreeNode root) {
+
+        Queue<TreeNode> q = new LinkedList<>();
+
+        int level = 0;
+        int ans = 1;
+        int ansLevel = 0;
+        int ansVal = -100000;
+
+        q.add(root);
+
+        while (!q.isEmpty()) {
+            ansLevel++;
+
+            int size = q.size();
+            int sum = 0;
+
+            for (int i = 0; i < size; i++) {
+                TreeNode node = q.poll();
+                sum += node.val;
+
+                if (node.left != null) {
+                    q.add(node.left);
+                }
+                if (node.right != null) {
+                    q.add(node.right);
+                }
+            }
+
+            if (sum > ansVal) {
+                ans = ansLevel;
+                ansVal = sum;
+            }
+        }
+        return ans;
+    }
+}
+```
+
+* 너무나도 무난했던 BFS 유형의 문제
+
+* 다시 풀 필요 X
+
+---
+
+## Reference
+
+* [1161. Maximum Level Sum of a Binary Tree](https://leetcode.com/problems/maximum-level-sum-of-a-binary-tree)