My solutions to the Qualification Round of Google Code Jam. You can find the questions here https://code.google.com/codejam/contest/2974486/dashboard

Pset1.java

/**
 * Google Code Jam 1
 * Pset1.java
 */
 
import java.io.*;
import java.util.Scanner;

public class Pset1 {

    public static void main(String[] args) throws Exception {
        File file = new File("A-small-attempt2.in");
        File outFile = new File("A-small-attempt2.out");
        Scanner stdIn = new Scanner(file); //read input from file
        PrintWriter pw = new PrintWriter(outFile); //write output to outFile
        int tests; // casess of test, [1;100]
        int cases=1;
        int row1=0,row2=0; // row of card for the 1st and 2nd time
        int[][] cards1 = new int[4][4]; //matrix of cards for the 1st time
        int[][] cards2 = new int[4][4]; //matrix of cards for the 2nd time
		int numbersMatch = 0;
		int flag=0;

                                                                                                         
        //read the number of tests from the file
        tests = stdIn.nextInt();
        if(tests<0 || tests>100) { //error on this cases
            return;
        }

        for(int i=0;i<tests;i++) {
                //read the 1st row
                row1 = stdIn.nextInt();
				row1--;
                //read the first arrange
                for (int a=0;a<4;a++) {
					for(int b=0;b<4;b++) {
						cards1[a][b] = stdIn.nextInt();
					}
				}
				
                //read the 2nd row
                row2 = stdIn.nextInt();
				row2--;
				//read the 2nd arrange
                for (int a=0;a<4;a++) {
					for(int b=0;b<4;b++) {
						cards2[a][b] = stdIn.nextInt();
					}
				}
				
                //check if any of the cards in cards1's row1 is also in cards2's row2
                for (int count=0;count<4;count++) {
				    for(int cnt=0;cnt<4;cnt++) {
						if(cards1[row1][count] == cards2[row2][cnt]) { //match found			
							numbersMatch++;
							flag = cnt;
						}
					}
                }

				//work things out with flag and numbersMatch
				if(numbersMatch == 0) { //magician did not found anything
					pw.println(String.format("Case #%d: Volunteer cheated!",cases));
					
				}
				else if(numbersMatch == 1) { //magician found the card
					pw.println(String.format("Case #%d: %d",cases,cards2[row2][flag]));
				}
				else if (numbersMatch>1) pw.println(String.format("Case #%d: Bad magician!",cases));
				
				cases++;
				numbersMatch=0;
        }
		
		stdIn.close();
		pw.close();

    }
    
}

Pset2.java

/**
 * Google Code Jam
 * pset2.java
 */

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

public class Pset2 {
	public static void main(String[] args) throws Exception {
		File file = new File("B-large.in");
		File outFile = new File("OutputLarge.txt");
		Scanner input = new Scanner(file);
		PrintWriter pw = new PrintWriter(outFile);
		
		int tests; // between 1 and 100
		double C, F, X; //cookies per farm, cookie farm gain, max score
		double time = 0.0; //time to achieve X
		double cookieRate = 2.0; //rate of cookie multiply
		double timeForFarm = 0.0; 
		double timeForX = 0.0;
		double timeForXAfterFarm = 0.0 ;
		
		//read number of tests
		tests = input.nextInt();
		if(tests<1 || tests>100) {
			return;
		}
		
		//iterate over the file for tests times
		for (int i=0;i<tests;i++) { 
			//read C, F and X
			C = input.nextDouble();
			F = input.nextDouble();
			X = input.nextDouble();
			
			do {
				//calculate time to achieve X with current cookieRate
				timeForX = (double) X/cookieRate;
				//calculate time to achieve C with current cookieRate
				timeForFarm = (double) C/cookieRate;
				timeForXAfterFarm = timeForFarm + X/(cookieRate+F);
				
				if (timeForXAfterFarm < timeForX) { //buys a farm
					cookieRate += F;
					
					time += timeForFarm;
					if (timeForFarm * cookieRate > X) {
						time += X/cookieRate; 
					
						break;
					}
				}
				else {
					
					time += timeForX; 
					break;
				}
			} while(timeForX > timeForXAfterFarm);
			
			//print into file
			pw.println(String.format("Case #%d: %.7f",i+1,time));
			
			//reset variables
			time = 0.0;
			timeForFarm = 0.0;
			timeForX = 0.0;
			timeForXAfterFarm = 0.0;
			cookieRate = 2.0;	
			
		}
		
		input.close();
		pw.close();
		
	}
}

Pset3.java

/**
 * Google Code Jam
 * Pset3.java
 */

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

public class Pset3 {
	public static void main(String[] args) throws Exception {
		File file = new File("input.txt");
		File outFile = new File("Output.txt");
		Scanner input = new Scanner(file);
		PrintWriter pw = new PrintWriter(outFile);
		
		int T; //test cases
		int M; //number of mines
		int R,C; //dimensions of field
		
		//read the number of test cases
		T = input.nextInt();
		
		for (int i=0;i<T;i++) {
			
			//read dimensions
			R = input.nextInt();
			C = input.nextInt();
			//read number of mines
			M = input.nextInt();
			if (R*C-M<4) pw.println(String.format("Case #%d:\nImpossible",i+1));
			else if ( R*C-M==1 && (R==1 || C==1)) pw.println(String.format("Case #%d:\nImpossible",i+1));
			
			else { //ka zgjidhje ta haj dreqi :(
				for (int a=0;a<R-2;a++)
					print('*',C);
				System.out.print("..");
				print('*',C-2);
				System.out.print("c.");
				print('*',C-2);
				System.out.println("\n\n\n");

			}
			
		
		}
		
		input.close();
		pw.close();
		
	}
	
	static void print(char ch,int times) {
		for (int i=0;i<times;i++)
			System.out.print(ch);
		System.out.print("\n");
	}
}

Pset4.java

/**
 * Google Code Jam
 * Pset4.java
 */

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

public class Pset4 {
	public static void main(String[] args) throws Exception {
		File file = new File("D-large.in");
		File outFile = new File("OutputLarge.txt");
		Scanner input = new Scanner(file);
		PrintWriter pw = new PrintWriter(outFile);
		
		int testCases; //number of times the program will iterate
		int N; //number of blocks for each player
		List<Double> naomiWeights = null; //weights of Naomi
		List<Double> kenWeights = null; //weights of Ken
		int warScore=0; //score of Naomi while playing War
		int dwarScore=0; //score of Naomi while playing Deceitful War
		double tN; //number that Naomi tells to Ken in a Deceitful War game
		double cN,cK=0;

		//read testCases
		testCases = input.nextInt();
		System.out.println("testCases: "+testCases);
		if(testCases>51 || testCases<0) { //test cases out of bound
			System.exit(1); 
		}
		
		for (int i=0;i<testCases;i++) { //iterate over test cases
			//read number of blocks
			N = input.nextInt();
			System.out.println("N: "+N);
			
			naomiWeights = new ArrayList<>();
			kenWeights = new ArrayList<>();
			//read naomiWeights
			for(int nw=0;nw<N;nw++) naomiWeights.add(input.nextDouble());
			//read kenWeights
			for(int kw=0;kw<N;kw++) kenWeights.add(input.nextDouble());
			
			if(N==1) {
				if(kenWeights.get(0) < naomiWeights.get(0)) warScore = dwarScore = 1;
				//now print values into the outFile
				pw.println(String.format("Case #%d: %d %d",i+1,dwarScore,warScore));
				System.out.println(String.format("Case #%d: %d %d",i+1,dwarScore,warScore));
				System.out.println("\n\n");
				
				//reset variables in the end
				dwarScore=0;
				warScore=0;
				N=0;
				naomiWeights = null;
				kenWeights = null;
				continue;
			}
			
			//sort weights
			Collections.sort(naomiWeights);
			Collections.sort(kenWeights);
			List<Double> kenCopy = new ArrayList<>(kenWeights);
			
			System.out.println("naomiWeights: "+naomiWeights);
			System.out.println("kenWeights: "+kenWeights);
			
			/**
			 * Let's calculate how many points can Naomi win in a War game.
			 * She will win the same amount of weights that are bigger than
			 * Ken's, while looping from the end to the begginning of the array.
			 */
			for(int index=0;index<N;index++) {
				
				cN = tN = naomiWeights.get(index);
				//search for kN
				for(int l=0;l<kenCopy.size();l++) {
					if (kenCopy.get(l)>tN) {
						cK = kenCopy.get(l);
						break; //found the smaller weight bigger than tN
					}
					cK = kenCopy.get(l); //get the last if break is not reached
				}
				if (cN > cK) warScore++;
				kenCopy.remove(kenCopy.indexOf(cK));
			}	
			
			
			System.out.println("warScore: "+warScore);
			
			kenCopy = new ArrayList<>(kenWeights);
			/**
			 * Let's calculate how many points can Naomi win in a Deceitful War
			 * game. She throws her smaller weight and tells the average of 2 of
			 * Ken's bigger weights, in order to get rid of massive weights of Ken
			 */
			
			while (!kenCopy.isEmpty()) {
				
				if (naomiWeights.get(naomiWeights.size()-1) > kenCopy.get(kenCopy.size()-1) ) {
					dwarScore++;
					naomiWeights.remove(naomiWeights.size()-1);
					kenCopy.remove(kenCopy.size()-1);
				}
				
				else {
					if(kenCopy.size() == 1) { //every value removed
					cK = kenCopy.get(0);
					cN = naomiWeights.get(naomiWeights.size()-1);
					if (cN > cK) dwarScore++;
					break;
					}
					cN = naomiWeights.get(0);
					tN = (kenCopy.get(kenCopy.size()-1) + kenCopy.get(kenCopy.size()-2))/2;
					//search for kN
					cK = kenCopy.get(kenCopy.size()-1);
					//kenCopy.remove(kenCopy.size()-1);

					if (cN > cK) dwarScore++;
					kenCopy.remove(kenCopy.indexOf(cK));
				}
				
			
			}
			
			
			
			
			
			
			
			
			
			
			
			
			
			
			
			
			/*
			while(!kenCopy.isEmpty()) {
				
				if(kenCopy.size() == 1) { //every value removed
					cK = kenCopy.get(0);
					cN = naomiWeights.get(naomiWeights.size()-1);
					if (cN > cK) dwarScore++;
					break;
				}
				cN = naomiWeights.get(0);
				tN = (kenCopy.get(kenCopy.size()-1) + kenCopy.get(kenCopy.size()-2))/2;
				//search for kN
				cK = kenCopy.get(kenCopy.size()-1);
				//kenCopy.remove(kenCopy.size()-1);

				if (cN > cK) dwarScore++;
				kenCopy.remove(kenCopy.indexOf(cK));
				//index++;
				if(kenCopy.get(kenCopy.size()-1) < naomiWeights.get(naomiWeights.size()-1)) {
					dwarScore++;
					kenCopy.remove(kenCopy.size()-1);
					naomiWeights.remove(naomiWeights.size()-1);
				}
				
			}
			*/
			/*
			do {
				//krahaso max2 me max1
				if(kenCopy.get(kenCopy.size()-1) < naomiWeights.get(naomiWeights.size()-1)) {
					dwarScore++;
					kenCopy.remove(kenCopy.size()-1);
					naomiWeights.remove(naomiWeights.size()-1);
				}
				
				else {
					kenCopy.remove(kenCopy.size()-1);
					naomiWeights.remove(naomiWeights.size()-1);
				}
			}while(! kenCopy.isEmpty());
			*/
			System.out.println("dwarScore: "+dwarScore);
			
			//now print values into the outFile
			pw.println(String.format("Case #%d: %d %d",i+1,dwarScore,warScore));
			System.out.println(String.format("Case #%d: %d %d",i+1,dwarScore,warScore));
			System.out.println("\n\n");
			
			//reset variables in the end
			dwarScore=0;
			warScore=0;
			N=0;
			naomiWeights = null;
			kenWeights = null;
		
		}
		
		input.close();
		pw.close();
		
	}
	
}