Merge pull request #1052 from bus710/week12

[bus710] Week 12

Author: bus710

same-tree/bus710.go

@@ -0,0 +1,69 @@
+package hello
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func isSameTree(p, q *TreeNode) bool {
+	if p == nil && q == nil {
+		return true
+	}
+
+	return checker(p, q)
+}
+
+func checker(p, q *TreeNode) bool {
+	if eitherNilChecker(p, q) {
+		return false
+	}
+
+	if p.Val != q.Val {
+		return false
+	}
+
+	if !bothNilChecker(p.Left, q.Left) {
+		re := checker(p.Left, q.Left)
+		if !re {
+			return false
+		}
+	}
+	if !bothNilChecker(p.Right, q.Right) {
+		re := checker(p.Right, q.Right)
+		if !re {
+			return false
+		}
+	}
+
+	return true
+}
+
+func eitherNilChecker(p, q *TreeNode) bool {
+	if p == nil && q != nil {
+		return true
+	}
+	if p != nil && q == nil {
+		return true
+	}
+	if p.Left != nil && q.Left == nil {
+		return true
+	}
+	if p.Left == nil && q.Left != nil {
+		return true
+	}
+	if p.Right != nil && q.Right == nil {
+		return true
+	}
+	if p.Right == nil && q.Right != nil {
+		return true
+	}
+	return false
+}
+
+func bothNilChecker(p, q *TreeNode) bool {
+	if p == nil && q == nil {
+		return true
+	}
+	return false
+}