wushbin

class Solution {
    public String dayOfTheWeek(int day, int month, int year) {
        
        int dayDiff = getDayDiff(day, month, year);
        int currDayDiff = getDayDiff(9, 2, 2020);
        int diff = dayDiff - currDayDiff;
        int shift = diff % 7;
        shift = (shift + 7) % 7;
        String[] dict = {"Sunday", "Monday", "Tuesday", "Wednesday", "Thursday", "Friday", "Saturday"};
        int currDayIndex = 0;

wushbin

/**
Two pass solution
**/

class Solution {
    public String getHint(String secret, String guess) {
        if (secret == null || guess == null || secret.length() == 0 || guess.length() == 0) {
            return "";
        }
        int len = secret.length();

wushbin

class Solution {
    public String decodeString(String s) {
        if (s == null || s.length() == 0) {
            return "";
        }
        return decode(s.toCharArray(), new int[]{0});
    }
    
    public String decode(char[] s, int[] p) {
        StringBuilder result = new StringBuilder();

wushbin

class Solution {
    public int findMinDifference(List<String> timePoints) {
        List<Integer> times = new ArrayList<>();
        for (String tp : timePoints) {
            times.add(readValue(tp));
        }
        Collections.sort(times);
        
        int min = Integer.MAX_VALUE;
        int len = times.size();

wushbin

class Solution {
    public void rotate(int[][] matrix) {
        trans(matrix);
        flip(matrix);
    }
    
    private void trans(int[][] matrix) {
        int row = matrix.length;
        int col = matrix[0].length;
        for (int i = 0; i < row; i++) {

wushbin

class Solution {
    public int myAtoi(String str) {
        if (str == null || str.length() == 0) {
            return 0;
        }
        
        int ptr = 0;
        int len = str.length();
        while(ptr < len && str.charAt(ptr) == ' ') {
            ptr++;

wushbin

class Solution {
    public boolean isPalindrome(String s) {
        int l = 0;
        int r = s.length() - 1;
        while(l < r) {
            
            while(l < r && !Character.isLetter(s.charAt(l)) && !Character.isDigit(s.charAt(l)) ) {
                l++;
            }
            char lc = Character.toLowerCase(s.charAt(l));

wushbin

class Solution {
    public boolean validTicTacToe(String[] board) {
        int[] row = new int[3];
        int[] col = new int[3];
        int diag = 0;
        int anti = 0;
        int xMove = 0;
        int oMove = 0;
        for (int i = 0; i < 3; i++) {
            for (int j = 0; j < 3; j++) {

wushbin

class Solution {
    public String validIPAddress(String IP) {
        String[] ipv4 = IP.split("\\.");
        String[] ipv6 = IP.split("\\:");
        
        if (ipv4.length == 4) {
            if (countSep(IP, '.') > 3) {
                return "Neither";
            }
            for (int i = 0; i < 4; i++) {

wushbin

/**
Solution One
Two Pass
**/
class Solution {
    public String convert(String s, int numRows) {
        if (s == null || s.length() == 0 || numRows == 0) {
            return "";
        }
        if (numRows == 1) {