HackerRank

0-Day

Tutorials:Cracking the Code Interview
===========================
- Arrays: Left Rotation

Algorithms:Warmup
=================
- Simple Array Sum
- Compare the Triplets
- A Very Big Sum
- Diagonal Difference
- Plus Minus
- Staircase
- Time Conversion
- Circular Array Rotation

A Very Big Sum

import scala.math._

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var arr = new Array[Int](n);
        if (n >= 1 && n <= 10) {
            for(arr_i <- 0 to n-1) {
               arr(arr_i) = sc.nextInt();
            }
            
            if (arr.length >= 0 && arr.length <= pow(10, 10).toInt) {
                println(arr.map(_.toLong).sum)
            }
        }
    }
}

Arrays: Left Rotation

object Solution {
  
    def rotateLeft[A](seq: Seq[A], i: Int): Seq[A] = {
        val size = seq.size
        val (first, last) = seq.splitAt(i % size)
        last ++ first
    }

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var k = sc.nextInt();
        var a = new Array[Int](n);
        for(a_i <- 0 to n-1) {
           a(a_i) = sc.nextInt();
        }
      
        val b = rotateLeft(a, k)
        for (b_i <- 0 to n-1) {
          print(b(b_i) + " ") 
        }
    }
}

Circular Array Rotation

import scala.math._

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var k = sc.nextInt();
        var q = sc.nextInt();
        var a = new Array[Int](n);
        if (n >= 1 && n <= pow(10,5)) {
            for(a_i <- 0 to n-1) {
                a(a_i) = sc.nextInt();
            }

            var a0 = 0;
            if ((k >= 1 && k <= pow(10,5)) && (q >= 1 && q <= 500)) {
                if (k > n) k = k%n
                while(a0 < q){
                    var m = sc.nextInt();
                    if (m >= 0 && m <= n-1) println(a((n+m-k)%n))
                    a0+=1;
                }
            }
        }
    }
}

Compare the Triplets

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var a0 = sc.nextInt();
        var a1 = sc.nextInt();
        var a2 = sc.nextInt();
        var b0 = sc.nextInt();
        var b1 = sc.nextInt();
        var b2 = sc.nextInt();
      
      
        val aArr = Array(a0, a1, a2)
        val bArr = Array(b0, b1, b2)
        
        var aPoints = 0
        var bPoints = 0
          
        for (i <- 0 to 2) {
            if (aArr(i) > 1 && aArr(i) < 100) {
                if (bArr(i) > 1 && bArr(i) < 100) {
                    if (aArr(i) > bArr(i)) {
                        aPoints += 1
                    }
                    else if (aArr(i) < bArr(i)) {
                        bPoints += 1
                    }
                }
                else {
                    aPoints += 1
                }
            }
            else {
                if (bArr(i) > 1 && bArr(i) < 100) {
                    bPoints += 1
                }
            }
        }
          
        println(s"$aPoints $bPoints")
    }
}

Diagonal Difference

import scala.math._

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var a = Array.ofDim[Int](n,n);
        for(a_i <- 0 to n-1) {
           for(a_j <- 0 to n-1){
              a(a_i)(a_j) = sc.nextInt();
           }
        }
        
        var left = 0
        var right = 0
        for(a_i <- 0 to n-1) {
           for(a_j <- 0 to n-1){
              if (a_i == a_j) {
                  left += a(a_i)(a_j)
              }
              
              if (a_i+a_j == n-1) {
                  right += a(a_i)(a_j)
              }
           }
        }
        
        val diff = abs(left-right)
        println(s"$diff")
    }
}

Plus Minus

import scala.math._

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var arr = new Array[Int](n);
        
        var (a, b, c) = (0.0, 0.0, 0.0)
        for(arr_i <- 0 to n-1) {
            arr(arr_i) = sc.nextInt();
            if (signum(arr(arr_i)) > 0) {
                a += 1.0
            }
            else if (signum(arr(arr_i)) < 0) {
                b += 1.0
            }
            else {
                c += 1.0
            }
        }
        
        val (dA, dB, dC) = (a/n, b/n, c/n)
        println(f"$dA%.6f")
        println(f"$dB%.6f")
        println(f"$dC%.6f")
    }
}

Simple Array Sum

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        var arr = new Array[Int](n);
        for(arr_i <- 0 to n-1) {
           arr(arr_i) = sc.nextInt();
        }
       
        println(arr.map(_.toInt).sum)
    }
}

Staircase

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var n = sc.nextInt();
        
        for (i <- 1 to n) {
            for (j <- 1 to n) {
                if (i+j > n) {
                    print("#")
                }
                else {
                    print(" ")
                }
            }
            println()
        }
    }
}

Time Conversion

import java.text._

object Solution {

    def main(args: Array[String]) {
        val sc = new java.util.Scanner (System.in);
        var time = sc.next();
        
        val inf = new SimpleDateFormat("hh:mm:ssaa")
        val ouf = new SimpleDateFormat("HH:mm:ss")
            
        var date = inf.parse(time)
        val output = ouf.format(date)
            
        println(output)
    }
}