Apr 14

2024-04-April-LeetCoding-Challenge/README.md

@@ -16,7 +16,7 @@
 | April 11 | [402. Remove K Digits](https://leetcode.com/problems/remove-k-digits/) | Medium | Unsolved |
 | April 12 | []() |  |  |
 | April 13 | []() |  |  |
-| April 14 | []() |  |  |
+| April 14 | [404. Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/) | Easy | Solved |
 | April 15 | []() |  |  |
 | April 16 | []() |  |  |
 | April 17 | []() |  |  |
@@ -38,6 +38,6 @@
 ## Summary
 | Level  | Problems | Solved | Unsolved |
 | ---    | --- | --- | --- |
-| Easy   | 6 | 6 | 0 |
+| Easy   | 7 | 7 | 0 |
 | Medium | 5 | 2 | 3 |
 | Hard   | 0 | 0 | 0 |

2024-04-April-LeetCoding-Challenge/Sum of Left Leaves.py

@@ -0,0 +1,42 @@
+from typing import Optional
+
+
+# Definition for a binary tree node.
+class TreeNode:
+    def __init__(self, val=0, left=None, right=None):
+        self.val = val
+        self.left = left
+        self.right = right
+
+
+class Solution:
+    def sumOfLeftLeaves(self, root: Optional[TreeNode]) -> int:
+        queue = [root]
+        total_sum = 0
+        while queue:
+            next_queue = []
+            for node in queue:
+                if node.left:
+                    if not node.left.left and not node.left.right:
+                        total_sum += node.left.val
+                    next_queue.append(node.left)
+                if node.right:
+                    next_queue.append(node.right)
+            queue = next_queue
+        return total_sum
+
+
+def main():
+    root = TreeNode(3)
+    root.left = TreeNode(9)
+    root.right = TreeNode(20)
+    root.right.left = TreeNode(15)
+    root.right.right = TreeNode(7)
+    assert Solution().sumOfLeftLeaves(root) == 24
+
+    root = TreeNode(1)
+    assert Solution().sumOfLeftLeaves(root) == 0
+
+
+if __name__ == '__main__':
+    main()