Created average-of-levels-in-binary-tree.cpp

programs/average-of-levels-in-binary-tree.cpp

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+/*
+Given the root of a binary tree, return the average value of the nodes on each level in the form of an array. 
+*/
+
+struct TreeNode {
+     int val;
+     TreeNode *left;
+     TreeNode *right;
+     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ };
+
+class Solution {
+public:
+    vector<double> averageOfLevels(TreeNode* root) {
+        vector<double> result;
+        vector<TreeNode *> q;
+        q.emplace_back(root);
+        while (!q.empty()) {
+            long long sum = 0, count = 0;
+            vector<TreeNode *> next_q;
+            for (const auto& n : q) {
+                sum += n->val;
+                ++count;
+                if (n->left) {
+                    next_q.emplace_back(n->left);
+                }
+                if (n->right) {
+                    next_q.emplace_back(n->right);
+                }
+            }
+            swap(q, next_q);
+            result.emplace_back(sum * 1.0 / count);
+        }
+        return result;
+    }
+};