Create deepest-leaves-sum.cpp

Author: kamyu104

C++/deepest-leaves-sum.cpp

@@ -0,0 +1,32 @@
+// Time:  O(n)
+// Space: O(w)
+
+/**
+ * Definition for a binary tree node.
+ * struct TreeNode {
+ *     int val;
+ *     TreeNode *left;
+ *     TreeNode *right;
+ *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
+ * };
+ */
+class Solution {
+public:
+    int deepestLeavesSum(TreeNode* root) {
+        vector<TreeNode *> curr = {root}, prev;
+        while (!curr.empty()) {
+            prev = move(curr);
+            for (const auto& p : prev) {
+                for (const auto& child : {p->left, p->right}) {
+                    if (child) {
+                        curr.emplace_back(child);
+                    }
+                }
+            }
+        }
+        return accumulate(prev.cbegin(), prev.cend(), 0,
+                          [](const auto& x, const auto& y) {
+                              return x + y->val;
+                          });
+    }
+};