Minimum Level Sum of a Binary Tree

Author: anantkaushik

Facebook/Problem#117.py

@@ -0,0 +1,29 @@
+"""
+Given a binary tree, return the level of the tree with minimum sum.
+"""
+def minLevelSum(root):
+    level = minLevel = 0
+    if not root:
+        return minLevel
+
+    queue = [[root]]
+    minSum = float('inf')
+        
+    while queue:
+        level += 1
+        levelNodes = queue.pop(0)
+        nextLevel = []
+        levelSum = 0
+        while levelNodes:
+            node = levelNodes.pop()
+            levelSum +=node.val
+            if node.left:
+                nextLevel.append(node.left)
+            if node.right:
+                nextLevel.append(node.right)
+        if nextLevel:
+            queue.append(nextLevel)
+        if levelSum < minSum:
+            minSum = levelSum
+            minLevel = level
+    return minLevel