二叉搜索树的第k大节点

Author: hero

leet_code/kthLargest_test.go

@@ -0,0 +1,50 @@
+package leet_code
+
+import (
+	"testing"
+)
+
+//二叉搜索树的第k大节点
+func kthLargest(root *TreeNode, k int) int {
+	if root == nil {
+		return 0
+	}
+	var data []int
+	kthLargestV1(root, &data)
+	qSort(data)
+	return data[k-1]
+}
+
+func qSort(num []int) {
+	if len(num) <= 1 {
+		return
+	}
+	var (
+		start = 0
+		end   = len(num) - 1
+		mod   = num[0]
+	)
+	for start < end {
+		if mod < num[start+1] {
+			num[start], num[start+1] = num[start+1], num[start]
+			start++
+		} else {
+			num[start+1], num[end] = num[end], num[start+1]
+			end--
+		}
+	}
+	qSort(num[:start])
+	qSort(num[start+1:])
+}
+
+func kthLargestV1(root *TreeNode, d *[]int) {
+	if root == nil {
+		return
+	}
+	*d = append(*d, root.Val)
+	kthLargestV1(root.Left, d)
+	kthLargestV1(root.Right, d)
+}
+
+func Test_kthLargest(t *testing.T) {
+}