.\958.check-completeness-of-a-binary-tree ok

侯利朋 · 侯利朋 · commit 842b4a575603 · 2019-08-30T21:42:56.000+08:00
diff --git a/958.check-completeness-of-a-binary-tree-err.go b/958.check-completeness-of-a-binary-tree-err.go
@@ -0,0 +1,45 @@
+/*
+ * @lc app=leetcode id=958 lang=golang
+ *
+ * [958] Check Completeness of a Binary Tree
+ */
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */ err-------------------------------------
+// [1]
+// [1,2,null,4,5,6]
+// BFS 层次遍历，统计node个数，直到遇到第一个空节点为止
+func isCompleteTree(root *TreeNode) bool {
+	if root == nil {
+		return true
+	}
+
+	queue := []*TreeNode{}
+	queue = append(queue, root)
+	for len(queue) > 0 {
+		node := queue[0]
+		queue = queue[1:]
+		if node.Left == nil || node.Right == nil {
+			if node.Left == nil && node.Right != nil {
+				return false
+			}
+			break
+		}
+		queue = append(queue, node.Left, node.Right)
+	}
+
+	for len(queue) > 0 {
+		node := queue[0]
+		queue = queue[1:]
+		if node.Left != nil || node.Right != nil {
+			return false
+		}
+	}
+
+	return true
+}
diff --git a/958.check-completeness-of-a-binary-tree.go b/958.check-completeness-of-a-binary-tree.go
@@ -0,0 +1,40 @@
+/*
+ * @lc app=leetcode id=958 lang=golang
+ *
+ * [958] Check Completeness of a Binary Tree
+ */
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+// 0 ms
+// [1]
+// [1,2,null,4,5,6,]
+// BFS 层次遍历，直到遇到第一个空节点后，队列中应该全是空节点
+func isCompleteTree(root *TreeNode) bool {
+	if root == nil {
+		return true
+	}
+
+	queue := []*TreeNode{}
+	queue = append(queue, root)
+	for len(queue) > 0 {
+		node := queue[0]
+		queue = queue[1:]
+		if node == nil { // 直到找到第一个空节点
+			break
+		}
+		queue = append(queue, node.Left, node.Right)
+	}
+	// 空节点之后，应该全是空节点
+	for _, node := range queue {
+		if node != nil {
+			return false
+		}
+	}
+	return true
+}
