Merge pull request #161 from gostool/leetcode1104

add: leetcode 1104 solution

Author: halfrost

leetcode/1104.Path-In-Zigzag-Labelled-Binary-Tree/1104.Path In Zigzag Labelled Binary Tree.go

@@ -0,0 +1,43 @@
+package leetcode
+
+func pathInZigZagTree(label int) []int {
+	level := getLevel(label)
+	ans := []int{label}
+	curIndex := label - (1 << level)
+	parent := 0
+	for level >= 1 {
+		parent, curIndex = getParent(curIndex, level)
+		ans = append(ans, parent)
+		level--
+	}
+	ans = reverse(ans)
+	return ans
+}
+
+func getLevel(label int) int {
+	level := 0
+	nums := 0
+	for {
+		nums += 1 << level
+		if nums >= label {
+			return level
+		}
+		level++
+	}
+}
+
+func getParent(index int, level int) (parent int, parentIndex int) {
+	parentIndex = 1<<(level-1) - 1 + (index/2)*(-1)
+	parent = 1<<(level-1) + parentIndex
+	return
+}
+
+func reverse(nums []int) []int {
+	left, right := 0, len(nums)-1
+	for left < right {
+		nums[left], nums[right] = nums[right], nums[left]
+		left++
+		right--
+	}
+	return nums
+}

leetcode/1104.Path-In-Zigzag-Labelled-Binary-Tree/1104.Path In Zigzag Labelled Binary Tree_test.go

@@ -0,0 +1,45 @@
+package leetcode
+
+import (
+	"fmt"
+	"testing"
+)
+
+type question1104 struct {
+	para1104
+	ans1104
+}
+
+// para 是参数
+type para1104 struct {
+	label int
+}
+
+// ans 是答案
+type ans1104 struct {
+	ans []int
+}
+
+func Test_Problem1104(t *testing.T) {
+
+	qs := []question1104{
+
+		{
+			para1104{14},
+			ans1104{[]int{1, 3, 4, 14}},
+		},
+
+		{
+			para1104{26},
+			ans1104{[]int{1, 2, 6, 10, 26}},
+		},
+	}
+
+	fmt.Printf("------------------------Leetcode Problem 1104------------------------\n")
+
+	for _, q := range qs {
+		_, p := q.ans1104, q.para1104
+		fmt.Printf("【input】:%v      【output】:%v      \n", p, pathInZigZagTree(p.label))
+	}
+	fmt.Printf("\n\n\n")
+}

leetcode/1104.Path-In-Zigzag-Labelled-Binary-Tree/README.md

@@ -0,0 +1,47 @@
+# [1104. Path In Zigzag Labelled Binary Tree](https://leetcode-cn.com/problems/path-in-zigzag-labelled-binary-tree/)
+
+
+## 题目
+
+In an infinite binary tree where every node has two children, the nodes are labelled in row order.
+
+In the odd numbered rows (ie., the first, third, fifth,...), the labelling is left to right, while in the even numbered rows (second, fourth, sixth,...), the labelling is right to left.
+
+![](https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/28/tree.png)
+
+Given the label of a node in this tree, return the labels in the path from the root of the tree to the node with that label.
+
+
+**Example 1:**
+
+    Input: label = 14
+    Output: [1,3,4,14]
+
+**Example 2:**
+
+    Input: label = 26
+    Output: [1,2,6,10,26]
+
+**Constraints:**
+
+1. `1 <= label <= 10^6`
+
+## 题目大意
+
+在一棵无限的二叉树上，每个节点都有两个子节点，树中的节点 逐行 依次按 “之” 字形进行标记。
+
+如下图所示，在奇数行（即，第一行、第三行、第五行……）中，按从左到右的顺序进行标记；
+
+而偶数行（即，第二行、第四行、第六行……）中，按从右到左的顺序进行标记。
+
+![](https://assets.leetcode-cn.com/aliyun-lc-upload/uploads/2019/06/28/tree.png)
+
+给你树上某一个节点的标号 label，请你返回从根节点到该标号为 label 节点的路径，该路径是由途经的节点标号所组成的。
+
+
+
+## 解题思路
+
+- 计算出label所在的level和index
+- 根据index和level计算出父节点的index和value
+- level减一,循环计算出对应的父节点直到根节点