add new files

Author: anakin

530. Minimum Absolute Difference in BST.go

@@ -0,0 +1,40 @@
+package main
+
+import (
+	"math"
+)
+
+type TreeNode struct {
+	Val   int
+	Left  *TreeNode
+	Right *TreeNode
+}
+
+var st []int
+
+func inorder(root *TreeNode) {
+	if root == nil {
+		return
+	}
+	if root.Left != nil {
+		inorder(root.Left)
+	}
+	if root != nil {
+		st = append(st, root.Val)
+	}
+	if root.Right != nil {
+		inorder(root.Right)
+	}
+}
+
+func getMinimumDifference(root *TreeNode) int {
+	st = make([]int, 0, 256)
+	inorder(root)
+	ret := math.MaxInt32
+	for i := 1; i < len(st); i++ {
+		if (st[i] - st[i-1]) < ret {
+			ret = st[i] - st[i-1]
+		}
+	}
+	return ret
+}

532. K-diff Pairs in an Array.go

@@ -0,0 +1,19 @@
+package main
+
+func findPairs(nums []int, k int) int {
+	if len(nums) == 0 || k < 0 {
+		return 0
+	}
+	m := map[int]int{}
+	for k, v := range nums {
+		m[v] = k
+	}
+	res := 0
+	for i := 0; i < len(nums); i++ {
+		if val, ok := m[nums[i]+k]; ok && val != i {
+			delete(m, nums[i]+k)
+			res++
+		}
+	}
+	return res
+}

541. Reverse String II.go

@@ -0,0 +1,18 @@
+package main
+
+func reverseStr(s string, k int) string {
+	t := []byte(s)
+	for l := 0; ; l += 2 * k {
+		r := l + k - 1
+		if r >= len(t) {
+			r = len(t) - 1
+		}
+		for i := l; i < r; i, r = i+1, r-1 {
+			t[i], t[r] = t[r], t[i]
+		}
+		if (l + 2*k) >= len(t) {
+			break
+		}
+	}
+	return string(t)
+}

543. Diameter of Binary Tree.go

@@ -0,0 +1,28 @@
+package main
+
+var ret int
+
+//直径等于left最大深度+right最大深度+1
+func helper(root *TreeNode) int {
+	if root == nil {
+		return 0
+	}
+	left := helper(root.Left)
+	right := helper(root.Right)
+	if ret < left+right+1 {
+		ret = left + right + 1
+	}
+	if left > right {
+		return left + 1
+	}
+	return right + 1
+}
+
+func diameterOfBinaryTree(root *TreeNode) int {
+	ret = 0
+	helper(root)
+	if ret == 0 {
+		return ret
+	}
+	return ret - 1
+}

551. Student Attendance Record I.go

@@ -0,0 +1,15 @@
+package main
+
+import "strings"
+
+func checkRecord(s string) bool {
+	t := strings.Count(s, "A")
+	if t >= 2 {
+		return false
+	}
+	t = strings.Count(s, "LLL")
+	if t > 0 {
+		return false
+	}
+	return true
+}