poker.java

/***
 * Project Euler: Poker hands, Problem 54
 * http://projecteuler.net/problem=54
 * Each line of the file "poker.txt" contains ten cards (separated by a single space): the first five are Player 1's cards and the last five are Player 2's cards. 
 * You can assume that all hands are valid (no invalid characters or repeated cards), 
 * each player's hand is in no specific order, and in each hand there is a clear winner.
 * The results are written to file "winners.txt"
 ***/

import java.util.*;
import java.io.*;

public class poker {
	String reason = ""; //updated by each function to write the reason for when a hand wins
	
    public poker(){               
    }
       
    //Royal Flush: Ten 'T', Jack, Queen, King, Ace, in same suit
    public int royal_flush(String hands){
        	
    	String h1 = hands.substring(0,14);
    	String h2 = hands.substring(15,29);
    	
    	int h1_royal = 0, h2_royal = 0;
    	
    	//check if the hands contains the following card values
    	if(h1.contains("T") && h1.contains("J") && h1.contains("K") && h1.contains("Q") && h1.contains("A"))
    		h1_royal = 1;
    		
    	if(h2.contains("T") && h2.contains("J") && h2.contains("K") && h2.contains("Q") && h2.contains("A"))
    		h2_royal = 1;
    	
    	//both players have royal flush
  		if(h1_royal == 1 && h2_royal == 1)
  			return 3; //tie
  		else if (h2_royal == 1){
  			reason = "P2 has Royal Flush.";
  			return 2; //player 2 wins
  		}
    	else if (h1_royal == 1){
    		reason = "P1 has Royal Flush.";
  			return 1; //player 1 wins
    	}
  		else
    		return 0; //no one has royal flush	
    }
    
    //straight flush All cards are consecutive values of same suit.
    public int straight_flush(String hands){
    	
    	int flush = flush(hands);
    	
    	if(flush == 0)//no one has flush
    		return 0; //no one has straigh flush
    	else{//check for straight
    		int straight = straight(hands);
    		
    		//both players have straight flush
  			if(straight == 3)
  				return 3; //tie
	  		else if (straight == 2){
	  			reason = "P2 has Royal Straight Flush.";
	  			return 2; //player 2 has straight flush
	  		}else if (straight == 1){
	  			reason = "P1 has Royal Straight Flush.";
	  			return 1; //player 1 has straight flush
    		}else
	    		return 0; //no one has straight flush	
    	}    	    	    	
    }
    
    //Four of a Kind: Four cards of the same value.
    public int four_kind(String hands){
    	//split based on characters, if array return is 5 then you have 4 of a kind
    	String[] card_values = {"2", "3", "4", "5", "6", "7", "8", "9", "T", "J", "Q", "K", "A"};
    	String h1 = hands.substring(0,14);
    	String h2 = hands.substring(15,29);
    	int h1_four = 0, h2_four = 0, i=0;
    	String h1_kind="", h2_kind="";
    	
    	for(i = 0; i< card_values.length; i++){
    	
    		if((h1.split(card_values[i])).length == 5){
    			h1_four = 1;
    			h1_kind = card_values[i];
    			break;
    		}
    	}
    	
    	for(i = 0; i< card_values.length; i++){
    	
    		if((h2.split(card_values[i])).length == 5){
    			h2_four = 1;
    			h2_kind = card_values[i];
    			break;
    		}
    	}
    	//both players have four kind
  		if(h1_four == 1 && h2_four == 1)
  			return 3; //tie
  		else if (h2_four == 1){
  			reason = "P2 has Four Kind of "+h2_kind;
  			return 2; //player 2 has four kind
  		}else if (h1_four == 1){
    		reason = "P1 has Four Kind of "+h1_kind;
  			return 1; //player 1 has four kind
  		}else
    		return 0; //no one has four kind
    	
    }
    //Full House: Three of a kind and a pair.
    public int full_house(String hands){
    	//split based on characters, if array return is 4 then you have 3 of a kind
    	String[] card_values = {"2", "3", "4", "5", "6", "7", "8", "9", "T", "J", "Q", "K", "A"};
    	String h1 = hands.substring(0,14);
    	String h2 = hands.substring(15,29);
    	int h1_three = 0, h2_three = 0, i=0, h1_pair=0, h2_pair=0;
    	String h1_kind_value="",h2_kind_value=""; //to keep the value of the card pair
    	
    	for(i = 0; i< card_values.length; i++){
    	
    		if((h1.split(card_values[i])).length == 4){
    			h1_three = 1;
    			h1_kind_value = card_values[i];
    			break;
    		}    		
    	}
    	
    	for(i = 0; i< card_values.length; i++){
    	
    		if((h2.split(card_values[i])).length == 4){
    			h2_three = 1;
    			h2_kind_value = card_values[i];
    			break;
    		}
    	}
    	//check for a pair in both hands if they have 3 of the same kind
    	if(h1_three == 1){
    		for(i = 0; i< card_values.length; i++){
    	
	    		if((h1.split(card_values[i])).length == 3){
	    			h1_pair = 1;
	    			break;
	    		}    		
    		}
    	}
    	if(h2_three == 1){
    	
	    	for(i = 0; i< card_values.length; i++){
	    	
	    		if((h2.split(card_values[i])).length == 3){
	    			h2_pair = 1;
	    			break;
	    		}
	    	}
    	}
    	
    	//both players have full house. 
  		if(h1_pair == 1 && h2_pair == 1){
  			//check which has the highest 3 kind value.
  			if(Integer.parseInt(h1_kind_value) < Integer.parseInt(h2_kind_value)){ 
  				reason = "P1 has a Full House. With three "+h2_kind_value+".";
  				return 2; //player 2 has full house
  			}
  			else if(Integer.parseInt(h1_kind_value) > Integer.parseInt(h2_kind_value)){ 
  				reason = "P1 has a Full House. With three "+h1_kind_value+".";
  				return 1; //player 1 has full house
  			}
  			return 3; //tie
  		}else if (h2_pair == 1){
  			reason ="P2 has a Full House.";
  			return 2; //player 2 has full house
  		}else if (h1_pair == 1){
    		reason ="P1 has a Full House.";
  			return 1; //player 1 has full house
  		}else
    		return 0; //no one has full house    	    	
    }
    
    //Flush: All cards are of same suit.
    public int flush(String hands){   	
    	
    	String h1 = hands.substring(0,14);
    	String h2 = hands.substring(15,29);
    	
    	int h1_equal = 1, h2_equal = 1;
    	
    	//use == if comparing primitive types
    	//check the suit characters in the string
    	for(int i = 1; i<13;i=i+3){
    		//check next couple of card suit as long as the one before equals to the next.
    		if(h1_equal==1 && h1.charAt(i) == h1.charAt(i+3))
    			h1_equal = 1;
    		else
    			h1_equal = 0;
    		if(h2_equal==1 && h2.charAt(i) == h2.charAt(i+3))
    			h2_equal = 1;
    		else
    			h2_equal = 0;
    	}
    	
    	//both players have flush
  		if(h1_equal == 1 && h2_equal == 1)
  			return 3; //tie
  		else if (h2_equal == 1){
  			reason = "P2 has a Flush. All cards of same suit";
  			return 2; //player 2 has flush
  		}else if (h1_equal == 1){
    		reason = "P1 has a Flush. All cards of same suit";
  			return 1; //player 1 has flush
    	}else
    		return 0; //no one has flush
    }
    
    //Straight: All cards are consecutive values.
    public int straight(String hands){
    	
    	int[] h = new int[10];    	
    	int m = 0;
    	
    	//convert cards to their decimal values
    	for(int i = 0; i< hands.length(); i+=3)
    		h[m++] = card_value(hands.charAt(i));
    		
    	//seperate players hands
    	int[] h1 = Arrays.copyOfRange(h, 0, 5);
    	int[] h2 = Arrays.copyOfRange(h, 5, 10);
    	
    	//sort arrays
    	Arrays.sort(h1);
    	Arrays.sort(h2);
    	
    	//assume sorted
    	int h1_ordered = 1, h2_ordered = 1; 
    		
    	for(int i = 1; i<h1.length -1 ;i++){
    		if(h1_ordered==1 && h1[i] == h1[i+1]-1 )
    			h1_ordered = 1;
    		else
    			h1_ordered = 0;
    		if(h2_ordered==1 && h2[i] == h2[i+1]-1)
    			h2_ordered = 1;
    		else
    			h2_ordered = 0;
    	}
    	
    	//both players have straight
  		if(h1_ordered == 1 && h2_ordered == 1)
  			return 3; //tie
  		else if (h2_ordered == 1){
  			reason = "P2 has a Straight. All cards are consecutive values.";
  			return 2; //player 2 has straight
  		}else if (h1_ordered == 1){
    		reason = "P1 has a Straight. All cards are consecutive values.";
  			return 1; //player 1 has straight
    	}else
    		return 0; //no one has straight	
    }
    
    
    public int n_kind(String hands, int kind, int pair){
    	//split based on characters, if array return is 4 then you have 3 of a kind
    	String[] card_values = {"2", "3", "4", "5", "6", "7", "8", "9", "T", "J", "Q", "K", "A"};
    	String h1 = hands.substring(0,14);
    	String h2 = hands.substring(15,29);
    	int h1_kind = 0, h2_kind = 0, i=0;
    	int h1_pair = 0, h2_pair = 0; 
    		
    	int h1_value = 0, h2_value = 0;   	    	    	
    	
    	for(i = 0; i< card_values.length; i++){
    		if((h1.split(card_values[i])).length == kind){
    			if(h1_pair == pair){
    				h1_kind = 1;
    				
    				if(card_value((card_values[i]).charAt(0)) > h1_value)
    					h1_value = (card_values[i]).charAt(0);
    				
    				break;
    			}
    			else
    				h1_pair++;
    			
    		}    		
    	}
    	
    	for(i = 0; i< card_values.length; i++){
    	
    		if((h2.split(card_values[i])).length == kind){
    			if(h2_pair == pair){
    				h2_kind = 1;
    				
    				if(card_value((card_values[i]).charAt(0)) > h2_value)
    					h2_value = (card_values[i]).charAt(0);
    					
    				break;
    			}
    			else
    				h2_pair++;
    		}
    	}
    	
    	//both players have n kind
  		if(h1_kind == 1 && h2_kind == 1){
  			
  			if(h1_value == h2_value){  			  			
  				reason = "P1 and P2 have "+(kind-1)+" kinds & "+(pair+1)+" pairs.";
  				return 3; //tie
  			}
  			//check the kind with the highest value.
  			else if(h1_value < h2_value){ 
  				reason = "P2 has "+(kind-1)+" kinds & "+(pair+1)+" pairs.";
  				return 2; //player 2 has n kind
  			}
  			else if(h1_value > h2_value){ 
  				reason = "P1 has "+(kind-1)+" kinds & "+(pair+1)+" pairs.";
  				return 1; //player 1 has n kind
  			}
  		}else if (h2_kind == 1){
  			reason = "P2 has "+(kind-1)+" kinds & "+(pair+1)+" pairs.";
  			return 2; //player 2 has n kind
  		}else if (h1_kind == 1){
  			reason = "P1 has "+(kind-1)+" kinds & "+(pair+1)+" pairs.";
  			return 1; //player 1 has n kind
  		}else
    		return 0; //no one has n kind
    		
    	return 0;	    	    	    	
    }
    
    // High Card: Highest value card.
    public int high_card(String hands){
    	int[] h = new int[10];
    	int m = 0;
    	
    	for(int i = 0; i< hands.length(); i+=3)
    		h[m++] = card_value(hands.charAt(i));    	
    	
    	int[] h1 = Arrays.copyOfRange(h, 0, 5);
    	int[] h2 = Arrays.copyOfRange(h, 5, 10);
    	
    	//sort arrays
    	Arrays.sort(h1);
    	Arrays.sort(h2);
    	
    	int h1_high = 0, h2_high=0;
    	
    	//compare card values
    	for(int i= h1.length-1; i>=0 ;i--){
    		if(h1[i] > h2[i]){
    			h1_high = 1;
    			break;
    		}else if(h2[i] > h1[i]){
    			h2_high = 1;
    			break;
    		}
    	}
    	
    	if(h1_high == 1 && h2_high == 1)
    		return 3; //tie
    	else if(h2_high == 1){
    		reason = reason+ " P2 has the highest value card.";
    		return 2; //player 2 wins
    	}else if(h1_high == 1){
    		reason = reason+ " P1 has the highest value card.";
    		return 1; //player 1 wins
    	}else
    		return 0; //tie
    	
    }
    //print out the final winner
    public String final_result (int win, String hand) {
    	int highest_hand=0;
    	
    	if(win == 1)
        		return "P1 wins!";
        else if(win == 2)
        		return "P2 wins!";
        else if(win == 3){
        	highest_hand = high_card(hand);
        		
        	if(highest_hand == 1)
        		return "P1 wins!";
        	else if(highest_hand == 2)
        		return "P2 wins!";
        	else if(highest_hand == 3 || highest_hand == 0)
        		return "Tie!!!";
        		
       }
       return "Error!";	
       	
    }
    
    public int card_value(char c){
    	int v = 0;
    	if(c == 'T')
    		v = 10;    			
    	else if (c == 'J')
    		v = 11; 
    	else if (c == 'Q')
    		v = 12; 
    	else if (c == 'K')
    		v = 13; 
    	else if (c == 'A')
    		v = 14; 
    	else
    		v = Character.getNumericValue(c);
    	
    	return v;	    			
    		    	 			 	
    }
    public static void main(String[] args) {

		String hand="";
		        
        int royal_flush=0, straight_flush=0, four_kind=0, full_house=0, flush=0, straight=0;
        int two_pairs = 0, one_pair, high_card=0, three_kind = 0;
        
        poker game = new poker();                
        
        try{
	        
	        // Open the file to read from
			FileInputStream fstream = new FileInputStream("poker.txt");
			BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
			
			// Open the file to write to			
			FileOutputStream fout = new FileOutputStream("winners.txt");
			BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(fout));
	
			bw.write("Player 1\t\tPlayer 2\t\tWinner\t\t\tReason\n");
			//Read File Line By Line
			while ((hand = br.readLine()) != null)   {
				game.reason="";
	  			
    			bw.write(hand.substring(0,14));
    			bw.write("\t\t");
    			bw.write(hand.substring(15,29));
    			bw.write("\t\t");
	  			
	  			royal_flush = game.royal_flush(hand);
	  			
	  			//no royal flush
		        if(royal_flush == 0){        	
		        	straight_flush = game.straight_flush(hand);
		        	
		        	//no straight flush
		        	if(straight_flush == 0){
		        		
		        		four_kind = game.four_kind(hand);
		        		
		        		//no four kind
		        		if (four_kind == 0){
		        			full_house = game.full_house(hand);
		        			
		        			//no full house
		        			if(full_house == 0){
		        				flush = game.flush(hand);
		        				
		        				//no flush
		        				if(flush == 0){
		        					straight = game.straight(hand);
		        					
		        					if(straight == 0){
		        						//check if 3 kind
		        						three_kind = game.n_kind(hand, 4, 0);
		        						
		        						if(three_kind == 0){
		        							two_pairs = game.n_kind(hand, 3, 1);
		        							
		        							if(two_pairs == 0){
		        								one_pair = game.n_kind(hand, 3, 0);
		        								
		        								if(one_pair == 0){        								
		        									high_card = game.high_card(hand);
		        									bw.write(game.final_result(high_card, hand));
		        								}
		        								else{
		        									bw.write(game.final_result(one_pair, hand));
		        								}
		        							}
		        							else{
		        								bw.write(game.final_result(two_pairs, hand));
		        							}
		        							
		        							}
		        						else{
		        							bw.write(game.final_result(three_kind, hand));
		        						}
		        						
		        					}
		        					else{
		        						bw.write(game.final_result(straight, hand));
		        					}
		        				}
		        				else{
		        					bw.write(game.final_result(flush, hand));	
		        				}
		        			}
		        			else{
		        				bw.write(game.final_result(full_house, hand));
		        			}
		        		}
		        		else{
		        			bw.write(game.final_result(four_kind, hand));
		        		}
		        	}
		        	else{//there is a straight flush
		        		bw.write(game.final_result(straight_flush, hand));
		        	}
		        	
		        }else{//there is a royal flush
		        	bw.write(game.final_result(royal_flush, hand));        	
		        }
        
		        bw.write("\t\t");
		        bw.write((game.reason).trim());
		        bw.write("\n");
			}
	
			//Close the input stream
			br.close();
			bw.close();
        }catch(IOException e){
        	System.out.println(e.getMessage());
        }          
    }  
}