Soluciones contest udp https://www.hackerrank.com/contests/udp-practica-solemne-1/challenges

Caballo.java

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

public class Solution {
    
    public static class Step {
        public int x, y, dist;
        
        public Step(int x, int y, int dist) {
            this.x = x;
            this.y = y;
            this.dist = dist;
        }   
    }
    
    public static void main(String[] args) {
        Queue<Step> q = new LinkedList<Step>();
        
        int[] mx = {-2, -2, -1, 1, 2,  2,  1, -1}; 
        int[] my = {-1,  1,  2, 2, 1, -1, -2, -2};
        
        Boolean[][] M = new Boolean[8][8];
        
        for(int i = 0; i<8;i++)
            for(int j = 0; j<8;j++)
                M[i][j]=false;
        
        Scanner stdIn = new Scanner(System.in);
        
        int cx, cy, ox, oy;
        Step tmp;
        
        cx = stdIn.nextInt();
        cy = stdIn.nextInt();
        ox = stdIn.nextInt();
        oy = stdIn.nextInt();
        
        q.add(new Step(cx, cy, 0));
        
        while(!q.isEmpty()) {
            tmp = q.remove();
            if(tmp.x == ox && tmp.y == oy){
                System.out.println(tmp.dist);
                break;
            }
            
            M[tmp.x][tmp.y] = true;
            
            for(int i=0;i<8;i++){
                if(tmp.x + mx[i] > 0 && tmp.x + mx[i] < 8 && tmp.y + my[i] > 0 && tmp.y + my[i] < 8 && !M[tmp.x + mx[i]][tmp.y + my[i]]) {
                    q.add(new Step(tmp.x + mx[i], tmp.y + my[i], tmp.dist+1));
                }
            }
        }
    }
}

Canciones.java

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

public class Solution {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = stdin.nextInt();
        
        Vector<Integer> songs = new Vector<Integer>();
        
        for(int i=0;i<n;i++) songs.add(stdin.nextInt());
        
        Set<Integer> set = new HashSet<Integer>(); 
        
        int max = 0, count = 0;
        for(int i=0;i<n;i++){
            if(!set.contains(songs.get(i))){
                set.add(songs.get(i));
                count++;
                if(max < count) max = count;
            } else {
                if(max < count) max = count;
                set.clear();
                count = 1;
                set.add(songs.get(i));
            }
        }
        
        System.out.println(max);
    }
}

Crecimiento.java

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

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner sdtin = new Scanner(System.in);
        int m,t,i;
        
        m = sdtin.nextInt();
        t = sdtin.nextInt();
        
        i = 0;
        while(true){
            if(m > t) break;
            m *= 3;
            t *= 2;
            i++;
        }
        System.out.println(i);
    }
}

DosCaballos.java

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

public class Solution {
    public static long solve(long i){
        if(i == 1) return 0;
        if(i == 2) return 6;
        long p = (long)Math.pow(i,2);
        return (p *(p-1) - 8*(i-1)*(i-2))/2;
    }
    
    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        long n = stdin.nextLong()+1;
        for(long i=1;i<n;i++){
            System.out.println(solve(i));
        }
    }
}

Invertir.java

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

public class Solution {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        String str = stdin.next();
        
        for(int i = str.length()-1; i>=0; i--){
            System.out.print(str.charAt(i));
        }
        System.out.print("\n");
    }
}

LeerLibros.java

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

public class Solution {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        long sum = 0;
        long buff;
        long max = Long.MIN_VALUE;
        int n = stdin.nextInt();
        
        for(int i=0;i<n;i++){
            buff = stdin.nextLong();
            if(buff > max) max = buff; 
            sum += buff;
        }
        
        if(sum-max < max) System.out.println(2*max);
        else System.out.println(sum);
    }
}

Manzana.java

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

public class Solution {
    public static class MinDiff {
        public int minDiff;
        
       public MinDiff() {
           this.minDiff = Integer.MAX_VALUE;
       }
        
       public void update(int minDiff) {
           if(minDiff<this.minDiff) this.minDiff = minDiff;
       }
    }
    
    public static void solve(Vector<Integer> v, int i, int lsum, int rsum, MinDiff minDiff){
        if(i >= v.size()) {
            minDiff.update(Math.abs(lsum - rsum));
            return;
        }
        solve(v, i+1, lsum+v.get(i),rsum, minDiff);
        solve(v, i+1, lsum,rsum+v.get(i), minDiff);
    }
    
    
    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = stdin.nextInt();
        Vector<Integer> v = new Vector<Integer>();
        for(int i =0;i<n;i++) v.add(stdin.nextInt());
        
        MinDiff minDiff = new MinDiff();
        solve(v, 0, 0, 0, minDiff);
        
        System.out.println(minDiff.minDiff);
    }
}

NumerosDistintos.java

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

public class Solution {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        
        int n = stdin.nextInt();
        int v;
        int count=0;
        
        Set<Integer> set = new TreeSet<Integer>();
        
        for(int i=0;i<n;i++){
            v = stdin.nextInt();
            if(!set.contains(v)) {
                count++;
                set.add(v);
            }
        }
        System.out.println(count);
    }
}

Repeticiones.java

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

public class Solution {

    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        String str = stdin.next();
        long count = 0;
        long max = 0;
        char actual = Character.MIN_VALUE;;
        
        for(char c:str.toCharArray()) {
            if(actual == c) {
                count++;
            } else {
                actual = c;
                count = 1;
            }
            if(max < count) max = count;
        }
        
        System.out.println(max);
    }
}

Rotacion.java

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

public class Solution {
    public static class Node{
        public int value;
        public Node next;
        
        public Node(int value) {
            this.value = value;
            this.next = null;
        }
    }
    
    public static class CircleList{
        public Node head;
        public Node tail;
        
        public CircleList() {
            this.head = null;
            this.tail = null;
        }
        
        public void insert(int value){
            Node n_node = new Node(value);
            
            if(this.head == null && this.tail == null) {
                n_node.next = n_node;
                this.head = this.tail = n_node;
            } else {
                this.tail.next = n_node;
                n_node.next = this.head;
                this.tail = n_node;   
            }
        }
        
        public void leftRotate() {
            this.head = this.head.next;
            this.tail = this.tail.next;
        }
        
        public void print() {
            if(this.head != null) {
                System.out.print(this.head.value);
                for(Node tmp=this.head.next;tmp!=this.head;tmp=tmp.next){
                    System.out.print(" " + tmp.value);
                }
                System.out.print("\n");
            }
        }
    }
    
    
    
    public static void main(String[] args) {
        Scanner stdin = new Scanner(System.in);
        int n = stdin.nextInt();
        int r = stdin.nextInt();
        CircleList cl = new CircleList();
        
        for(int i=0;i<n;i++){
            cl.insert(stdin.nextInt());
        }
        for(int i=0;i<r;i++){
            cl.leftRotate();
        }
        cl.print();
    }
}