20200516

Author: baxiang

129sum-root-to-leaf-numbers/main.go

@@ -0,0 +1,47 @@
+package main
+
+import "fmt"
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+func sumNumbers(root *TreeNode) int {
+	var res int
+	dfs(root, 0, &res)
+	return res
+}
+
+func dfs(root *TreeNode, val int, res *int) {
+	if root == nil {
+		return
+	}
+	val = val*10 + root.Val
+	if root.Left == nil && root.Right == nil {
+		*res = *res + val
+	}
+	dfs(root.Left, val, res)
+	dfs(root.Right, val, res)
+}
+
+func main() {
+	one := &TreeNode{Val: 1}
+	two := &TreeNode{Val: 2}
+	one.Left = two
+	three := &TreeNode{Val: 3}
+	one.Right = three
+	fmt.Println(sumNumbers(one))
+
+	four := &TreeNode{Val: 4}
+	nine := &TreeNode{Val: 9}
+	four.Left = nine
+	zero := &TreeNode{Val: 0}
+	four.Right = zero
+	five := &TreeNode{Val: 5}
+	nine.Left = five
+	one = &TreeNode{Val: 1}
+	nine.Right = one
+	fmt.Println(sumNumbers(four))
+}

32cong-shang-dao-xia-da-yin-er-cha-shu-lcof/main.go

@@ -0,0 +1,35 @@
+package main
+
+ type TreeNode struct {
+	     Val int
+	     Left *TreeNode
+	     Right *TreeNode
+	 }
+
+func levelOrder(root *TreeNode) []int {
+	var res []int
+	if root==nil{
+		return res
+	}
+	queue := []*TreeNode{root}
+	for len(queue)>0{
+		size :=len(queue)
+		for i:=0;i<size;i++{
+			node :=queue[i]
+			if node.Left!=nil{
+              queue = append(queue,node.Left)
+			}
+			if node.Right!=nil{
+				queue = append(queue,node.Right)
+			}
+			res = append(res,node.Val)
+		}
+		queue = queue[size:]
+	}
+	return res
+}
+
+//面试题32 - I. 从上到下打印二叉树
+func main() {
+	
+}

49chou-shu-lcof/main.go

@@ -0,0 +1,42 @@
+package main
+
+import "fmt"
+
+func nthUglyNumber(n int) int {
+	count := 0
+	number :=1
+	uglyNumber :=1
+    for count<n{
+    	if isUglyNum(number){
+    		count++
+			uglyNumber = number
+		}
+		number++
+	}
+	return uglyNumber
+}
+
+func isUglyNum(n int)bool{
+	for n%2==0{
+		n=n/2
+	}
+	for n%3==0{
+		n=n/3
+	}
+	for n%5==0{
+		n=n/5
+	}
+	return n<=1
+}
+
+//面试题49. 丑数
+func main() {
+    //fmt.Println(isUglyNum(2))
+	fmt.Println(nthUglyNumber(10))
+	fmt.Println(nthUglyNumber(11))
+	//for i:=1;i<=20;i++{
+	//	if isUglyNum(i){
+	//		fmt.Println(i)
+	//	}
+	//}
+}

53que-shi-de-shu-zi-lcof/main.go

@@ -0,0 +1,36 @@
+package main
+
+import "fmt"
+
+func missingNumber1(nums []int) int {
+    for i:=1;i<len(nums);i++{
+        if nums[i]-nums[i-1]!=1{
+        	return nums[i-1]+1
+		}
+	}
+	if nums[0]!=0{
+		return 0
+	}
+	return nums[len(nums)-1]+1
+}
+func missingNumber(nums []int) int {
+	left :=0
+	right :=len(nums)
+	for left<right{
+		mid := left+(right-left)>>1
+		if nums[mid]==mid{
+			left = mid+1
+		}else {
+			right = mid
+		}
+	}
+	return left
+}
+
+func main() {
+	fmt.Println(missingNumber([]int{0}))//1
+	fmt.Println(missingNumber([]int{1}))//0
+	fmt.Println(missingNumber([]int{0,1}))//2
+	fmt.Println(missingNumber([]int{0,1,3}))//2
+	fmt.Println(missingNumber([]int{0,1,2,3,4,5,6,7,9}))//8
+}