Category Archives: Java

UVA 11547 – Automatic Answer

I just used a double to avoid rounding errors. Then rounded at the end. Pretty easy.

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P11547 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    int T = sc.nextInt();
    while (T > 0) {
      double N = sc.nextDouble();
      double ans = (((N * 567.) / 9. + 7492) * 235. / 47.) - 498;
      ans /= 10;
      ans = Math.abs((long) ans);
      out.println((long) ans % 10);
      T--;
    }
    out.close();
    sc.close();
  }
}

UVA 11498 – Division of Nlogonia

I thought this question was going to be a lot more complicated than it turned out.

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P11498 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    int K = 0;
    while ((K = sc.nextInt()) != 0) {
      int N = sc.nextInt();
      int M = sc.nextInt();
      while (K > 0) {
        int X = sc.nextInt();
        int Y = sc.nextInt();
        if (X == N || Y == M) {
          out.println("divisa");
        } else if (X > N) {
          if (Y < M) {
            out.println("SE");
          } else {
            out.println("NE");
          }
        } else {
          if (Y < M) {
            out.println("SO");
          } else {
            out.println("NO");
          }
        }
        K--;
      }
    }
    out.close();
    sc.close();
  }

}

UVA 11364 – Parking

This one involves a bit of math. You will notice that it doesn’t matter where you park unless you park away from all of the shops.

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P11364 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    int T = sc.nextInt();
    while (T > 0) {
      int N = sc.nextInt();
      int min = Integer.MAX_VALUE;
      int max = Integer.MIN_VALUE;
      for (int i = 0; i < N; i++) {
        int next = sc.nextInt();
        min = Math.min(min, next);
        max = Math.max(max, next);
      }
      out.println(2 * (max - min));
      T--;
    }
    out.close();
    sc.close();
  }

}

UVA 11172 – Relational Operator

Really simple. Just a simple if-else.

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P11172 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    int N = Integer.parseInt(sc.nextLine());
    while (N > 0) {
      int X = sc.nextInt();
      int Y = sc.nextInt();
      if (X < Y) {
        out.println("<");
      } else if (X > Y) {
        out.println(">");
      } else {
        out.println("=");
      }
      N--;
    }
    out.close();
    sc.close();
  }

}

UVA 11044 – Searching for Nessy

I failed by misreading the problem on this one. I thought the sonar beam grid was of size 4 instead of size 3. It cost me two WA’s :(

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P11044 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    int N = Integer.parseInt(sc.nextLine());
    while (N &gt; 0) {
      int X = sc.nextInt();
      int Y = sc.nextInt();
      out.println((long) (Math.ceil((X - 2) * 1.0 / 3) * Math.ceil((Y - 2) * 1.0 / 3)));
      N--;
    }
    out.close();
    sc.close();
  }

}

UVA 10550 – Combination Lock

A bit of math but an otherwise really simple problem. I would have voted this as harder than the earlier problems as you need to figure out certain numbers based on the direction you are rotating.

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P10550 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    while (sc.hasNextLine()) {
      int degree = sc.nextInt();
      int first = sc.nextInt();
      int second = sc.nextInt();
      int third = sc.nextInt();
      if (first == second && second == third && third == degree && degree == first) {
        break;
      } else {
        out.println(doSolve(degree, first, second, third));
      }
    }
    out.close();
    sc.close();
  }

  private static long doSolve(int degree, int first, int second, int third) {
    // 40 numbers = 360 degrees. 1 number = 9 degrees.
    long ans = 0;
    // 2 clockwise turns.
    ans += 720;
    // To first number
    ans += 9 * findWay(degree, first, 0);
    // One counterclockwise turn
    ans += 360;
    // To second number
    ans += 9 * findWay(first, second, 1);
    // To third number
    ans += 9 * findWay(second, third, 0);
    return ans;
  }

  private static int findWay(int from, int to, int cw) {
    //Could memo this technically.
    
    int count = 0;
    if (cw == 1) {
      while (from != to) {
        from++;
        if (from == 40)
          from = 0;
        count++;
      }
    } else {
      while (from != to) {
        from--;
        if (from == -1)
          from = 39;
        count++;
      }
    }
    return count;
  }
}

UVA 1124 – Celebrity Jeopardy

Just re-print the input. There has to be a cooler way to do this in Java. I really want to just pipe the inputstream to the outputstream somehow.

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P1124 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    while (sc.hasNextLine()) {
      out.println(sc.nextLine());
    }
    out.close();
    sc.close();
  }

}

UVA 272 – TEX Quotes

This problem is super easy beacuse we are guaranteed that every quote is there an even number of times. Just replace the odd and even quotes in a different manner and you are set!

import java.io.PrintWriter;
import java.util.Scanner;

/**
 * 
 * @author Sanchit M. Bhatnagar
 * @see http://uhunt.felix-halim.net/id/74004
 * 
 */
public class P272 {

  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    PrintWriter out = new PrintWriter(System.out);
    boolean even = true;
    while (sc.hasNextLine()) {
      char[] line = sc.nextLine().toCharArray();
      for (Character c : line) {
        if (c == '"') {
          if (even) {
            out.print("``");
          } else {
            out.print("''");
          }
          even = !even;
        } else {
          out.print(c);
        }
      }
      out.print(System.lineSeparator());
    }
    out.close();
    sc.close();
  }

}

Factors

A naive way of figuring out the number of factors of a particular number is to try every number from 1 up to the number itself.

public ArrayList getFactors(int N) {
  ArrayList factors = new ArrayList();
  for (int i=0; i if (N%i==0) {
      factors.add(i);
  }
  return factors;
}

We can do much better than this by noticing that for every number i that is a factor of N; the number N/i is also a factor of N! This means that we can change out O(N) algorithm to O(sqrt(N)) which is much much faster.

F(x) vs F(sqrt(X))
O(N) algorithm vs O(sqrt(N)) algorithm
public ArrayList getFactors(int N) {
  ArrayList factors = new ArrayList();
  int sqrt = (int) Math.sqrt(N);
  for (int i=0; i if (N%i==0) {
    factors.add(i);
  }
  if (sqrt * sqrt == N) {
    factors.add(sqrt);
  }
  return factors;
}

Save this code somewhere, I guarantee it’ll come in handy!