Add minimum-depth-of-binary-tree

Author: Gituser143

Easy/minimum-depth-of-binary-tree.md

@@ -0,0 +1,52 @@
+Code
+====
+
+```go
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+func minDepth(root *TreeNode) int {
+	depth := 0
+	if root == nil {
+		return depth
+	}
+
+	level := []*TreeNode{root}
+
+	for len(level) != 0 {
+		newLevel := []*TreeNode{}
+		depth += 1
+		for _, node := range level {
+			if node.Left == nil && node.Right == nil {
+				return depth
+			}
+
+			if node.Left != nil {
+				newLevel = append(newLevel, node.Left)
+			}
+
+			if node.Right != nil {
+				newLevel = append(newLevel, node.Right)
+			}
+		}
+
+		level = newLevel
+	}
+
+	return depth
+}
+```
+
+Solution in mind
+================
+
+-	Perform a level order traversal using a queue.
+
+-	Increment depth on reaching new level. Compute next levels as children of current level.
+
+-	On encountering a leaf node, return depth as first leaf node encountered in level order will be of minimum depth.

README.md

@@ -67,6 +67,8 @@ Easy
 
 -	[maximum-depth-of-binary-tree](Easy/maximum-depth-of-binary-tree.md)
 
+-	[minimum-depth-of-binary-tree](Easy/minimum-depth-of-binary-tree.md)
+
 Medium
 ------