Merge pull request #211 from 0xff-dev/master

Add solution and test-cases for problem 653

Author: Cori1109

leetcode/601-700/0653.Two-Sum-IV--Input-is-a-BST/README.md

@@ -1,28 +1,43 @@
 # [653.Two Sum IV - Input is a BST][title]
 
-> [!WARNING|style:flat]
-> This question is temporarily unanswered if you have good ideas. Welcome to [Create Pull Request PR](https://github.com/kylesliu/awesome-golang-algorithm)
-
 ## Description
+Given the `root` of a Binary Search Tree and a target number `k`, return `true` if there exist two elements in the BST such that their sum is equal to the given target.
+
 
 **Example 1:**
+![example1](./sum_tree_1.jpg)
+```
+Input: root = [5,3,6,2,4,null,7], k = 9
+Output: true
+```
 
+__Example 2:__
+![example2](./sum_tree_2.jpg)
 ```
-Input: a = "11", b = "1"
-Output: "100"
+Input: root = [5,3,6,2,4,null,7], k = 28
+Output: false
 ```
 
-## 题意
-> ...
+__Example 3:__
 
-## 题解
+```
+Input: root = [2,1,3], k = 4
+Output: true
+```
 
-### 思路1
-> ...
-Two Sum IV - Input is a BST
-```go
+__Example 4:__
+
+```
+Input: root = [2,1,3], k = 1
+Output: false
 ```
 
+__Example 5:__
+
+```
+Input: root = [2,1,3], k = 3
+Output: true
+```
 
 ## 结语
 

leetcode/601-700/0653.Two-Sum-IV--Input-is-a-BST/Solution.go

@@ -1,5 +1,44 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func Solution(root *TreeNode, k int) bool {
+	nodes := make([]int, 0)
+	treeArray(root, &nodes)
+	return binarySearch(nodes, k)
+}
+
+func treeArray(root *TreeNode, nodes *[]int) {
+	if root == nil {
+		return
+	}
+	if root.Left != nil {
+		treeArray(root.Left, nodes)
+	}
+
+	*nodes = append(*nodes, root.Val)
+
+	if root.Right != nil {
+		treeArray(root.Right, nodes)
+	}
+}
+func binarySearch(nodes []int, target int) bool {
+	start, end := 0, len(nodes)-1
+	for start < end {
+		num := nodes[start] + nodes[end]
+		if num == target {
+			return true
+		}
+		if num < target {
+			start++
+			continue
+		}
+		end--
+	}
+
+	return false
 }

leetcode/601-700/0653.Two-Sum-IV--Input-is-a-BST/Solution_test.go

@@ -10,21 +10,46 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
+		inputs *TreeNode
+		target int
 		expect bool
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", &TreeNode{
+			Val: 5,
+			Left: &TreeNode{
+				Val:   3,
+				Left:  &TreeNode{Val: 2},
+				Right: &TreeNode{Val: 4},
+			},
+			Right: &TreeNode{
+				Val:   6,
+				Right: &TreeNode{Val: 7},
+			},
+		}, 9, true},
+		{"TestCase2", &TreeNode{
+			Val: 5,
+			Left: &TreeNode{
+				Val:   3,
+				Left:  &TreeNode{Val: 2},
+				Right: &TreeNode{Val: 4},
+			},
+			Right: &TreeNode{
+				Val:   6,
+				Right: &TreeNode{Val: 7},
+			},
+		}, 28, false},
+		{"TestCase3", &TreeNode{Val: 2, Left: &TreeNode{Val: 1}, Right: &TreeNode{Val: 3}}, 4, true},
+		{"TestCase4", &TreeNode{Val: 2, Left: &TreeNode{Val: 1}, Right: &TreeNode{Val: 3}}, 1, false},
+		{"TestCase4", &TreeNode{Val: 2, Left: &TreeNode{Val: 1}, Right: &TreeNode{Val: 3}}, 3, true},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.inputs, c.target)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v, target: %v",
+					c.expect, got, c.inputs, c.target)
 			}
 		})
 	}