alldroll

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func inorderSuccessor(root *TreeNode, p *TreeNode) *TreeNode {
    if root == nil || p == nil {

alldroll

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */

type LevelNode struct {

alldroll

const undefined = (1 << 31) - 1

func majorityElement(nums []int) int {
    candidate := undefined
    count := 0
    
    for _, num := range nums {
        if count == 0 {
            candidate = num
        }

alldroll

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func isValidBST(root *TreeNode) bool {
    return checkIsValid(root, -1 << 32, (1 << 32) - 1)

alldroll

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */

type OrderNode struct {

alldroll

/**
 * Definition for a binary tree node.
 * type TreeNode struct {
 *     Val int
 *     Left *TreeNode
 *     Right *TreeNode
 * }
 */
func isSubtree(s *TreeNode, t *TreeNode) bool {
    queue := []*TreeNode{s}

alldroll

const inf = (1 << 31) - 1

type pair struct {
    id int
    level int
}

func ladderLength(beginWord string, endWord string, wordList []string) int {
    graph := make(map[string][]int)
    

alldroll

// a1 + a2 + a3 + .. + an = n * (a1 + an) / 2
// 1 + 2 + 3 + 4 + 5
// 5 * (1 + 5) / 2 = 10

func arrangeCoins(n int) int {
    i, j := 1, n + 1
    
    for i < j {
        h := int(uint64(i + j) >> 1)
        sum := (h * (1 + h)) / 2

alldroll

var directions = [4][2]int{
    {0, 1},
    {1, 0},
    {0, -1},
    {-1, 0},
}

func findWords(board [][]byte, words []string) []string {
    rows := len(board)
    

alldroll

func numSquares(n int) int {
    // we are going to keep the minumum number of squares required to get the corresponding number
    // index here represents the desire number
    nums := make([]int, n + 1)
    
    // we calculate the minumum number of squares for each number from 1 to n
    for i := 1; i <= n; i++ {
        // as we have to get the minumum, at the first step we use INF as undefined number
        num := (1 << 31) - 1