BeyondSkyCoder

    public boolean isMatch(String s, String p) {
        if (p.length() == 0) {
            return s.length() == 0;
        }
         
        // case 1: when the second char of p is NOT '*', simple
        if (p.length() == 1 || p.charAt(1) != '*') {
            if (s.length() < 1) {
                return false;
            } else if ((p.charAt(0) != s.charAt(0)) && (p.charAt(0) != '.')) {

BeyondSkyCoder

import java.util.HashMap;
import java.util.HashSet;
import java.util.LinkedList;
import java.util.Map;
import java.util.Queue;
import java.util.Set;

public class AlienDictionary_graph {
    public String alienOrder(String[] words) {
    	if (words == null) return null;

BeyondSkyCoder

public class GasStation_greedy {
    public int canCompleteCircuit(int[] gas, int[] cost) {
        if (gas == null || cost == null || gas.length == 0 || cost.length == 0 || gas.length != cost.length)
            return -1;

        int len = gas.length;
        int delta = 0;
        int total = 0;
        int start_station = -1;
        

BeyondSkyCoder

import java.util.Arrays;

public class Candy_Greedy {
	// faster. two scans from left, then from right
    public int candyTwoScanFast(int[] ratings) {
        if (ratings == null || ratings.length == 0) return 0;
        
        int len = ratings.length;
        int tot = 0;
        int[] candy = new int[len];