规范格式

leetcode/0515.Find-Largest-Value-in-Each-Tree-Row/515. Find Largest Value in Each Tree Row.go

@@ -0,0 +1,94 @@
+package leetcode
+
+import (
+	"math"
+	"sort"
+)
+
+import (
+	"github.com/halfrost/LeetCode-Go/structures"
+)
+
+// TreeNode define
+type TreeNode = structures.TreeNode
+
+/**
+ * Definition for a binary tree node.
+ * type TreeNode struct {
+ *     Val int
+ *     Left *TreeNode
+ *     Right *TreeNode
+ * }
+ */
+
+// 解法一 层序遍历二叉树，再将每层排序取出最大值
+func largestValues(root *TreeNode) []int {
+	tmp := levelOrder(root)
+	res := []int{}
+	for i := 0; i < len(tmp); i++ {
+		sort.Ints(tmp[i])
+		res = append(res, tmp[i][len(tmp[i])-1])
+	}
+	return res
+}
+
+// this is 102 solution
+func levelOrder(root *TreeNode) [][]int {
+	if root == nil {
+		return [][]int{}
+	}
+	queue := []*TreeNode{}
+	queue = append(queue, root)
+	curNum, nextLevelNum, res, tmp := 1, 0, [][]int{}, []int{}
+	for len(queue) != 0 {
+		if curNum > 0 {
+			node := queue[0]
+			if node.Left != nil {
+				queue = append(queue, node.Left)
+				nextLevelNum++
+			}
+			if node.Right != nil {
+				queue = append(queue, node.Right)
+				nextLevelNum++
+			}
+			curNum--
+			tmp = append(tmp, node.Val)
+			queue = queue[1:]
+		}
+		if curNum == 0 {
+			res = append(res, tmp)
+			curNum = nextLevelNum
+			nextLevelNum = 0
+			tmp = []int{}
+		}
+	}
+	return res
+}
+
+// 解法二 层序遍历二叉树，遍历过程中不断更新最大值
+func largestValues1(root *TreeNode) []int {
+	if root == nil {
+		return []int{}
+	}
+	q := []*TreeNode{root}
+	var res []int
+	for len(q) > 0 {
+		qlen := len(q)
+		max := math.MinInt32
+		for i := 0; i < qlen; i++ {
+			node := q[0]
+			q = q[1:]
+			if node.Val > max {
+				max = node.Val
+			}
+			if node.Left != nil {
+				q = append(q, node.Left)
+			}
+			if node.Right != nil {
+				q = append(q, node.Right)
+			}
+		}
+		res = append(res, max)
+	}
+	return res
+}