hackerrank solutions added

Author: Ram swaroop

src/com/hackerrank/algorithms/arraysandsorting/InsertionSort1.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/1/15
+ * Time: 8:58 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class InsertionSort1 {
+
+    static void insertIntoSorted(int[] ar) {
+        int V = ar[ar.length - 1], i = ar.length - 2;
+
+        for (; i >= 0; i--) {
+            if (V < ar[i]) {
+                ar[i + 1] = ar[i];
+            } else {
+                break;
+            }
+            printArray(ar);
+        }
+
+        ar[i + 1] = V;
+        printArray(ar);
+    }
+
+    /* Tail starts here */
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int s = in.nextInt();
+        int[] ar = new int[s];
+        for (int i = 0; i < s; i++) {
+            ar[i] = in.nextInt();
+        }
+        insertIntoSorted(ar);
+    }
+
+    private static void printArray(int[] ar) {
+        for (int n : ar) {
+            System.out.print(n + " ");
+        }
+        System.out.println("");
+    }
+
+}

src/com/hackerrank/algorithms/arraysandsorting/InsertionSort2.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/1/15
+ * Time: 9:42 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class InsertionSort2 {
+
+    static void insertionSortPart2(int[] ar) {
+        for (int i = 1; i < ar.length; i++) {
+            int V = ar[i], j;
+            /**
+             * keep shifting no.s to right until
+             * right place for insertion(of V) is found
+             */
+            for (j = i - 1; j >= 0 && ar[j] > V; j--) {
+                ar[j + 1] = ar[j];
+            }
+            ar[j + 1] = V;
+            printArray(ar);
+        }
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int s = in.nextInt();
+        int[] ar = new int[s];
+        for (int i = 0; i < s; i++) {
+            ar[i] = in.nextInt();
+        }
+        insertionSortPart2(ar);
+
+    }
+
+    private static void printArray(int[] ar) {
+        for (int n : ar) {
+            System.out.print(n + " ");
+        }
+        System.out.println("");
+    }
+}

src/com/hackerrank/algorithms/arraysandsorting/IntroTutorial.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.Arrays;
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/1/15
+ * Time: 3:38 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class IntroTutorial {
+    static int search(int searchVal, int[] arr) {
+        return Arrays.binarySearch(arr, searchVal);
+    }
+
+    public static void main(String[] a) {
+        Scanner in = new Scanner(System.in);
+
+        int searchVal = in.nextInt();
+        int arrSize = in.nextInt();
+        int[] arr = new int[arrSize];
+        // as nextInt() doesn't read new line character
+        in.nextLine();
+        String next = in.nextLine();
+        String[] next_split = next.split(" ");
+
+        for (int _a_i = 0; _a_i < arrSize; _a_i++) {
+            arr[_a_i] = Integer.parseInt(next_split[_a_i]);
+        }
+
+        System.out.print(search(searchVal, arr));
+    }
+}

src/com/hackerrank/algorithms/arraysandsorting/LoopInvariant.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/2/15
+ * Time: 3:26 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class LoopInvariant {
+
+    public static void insertionSort(int[] A) {
+        for (int i = 1; i < A.length; i++) {
+            int value = A[i];
+            int j = i - 1;
+            while (j >= 0 && A[j] > value) {
+                A[j + 1] = A[j];
+                j = j - 1;
+            }
+            A[j + 1] = value;
+        }
+
+        printArray(A);
+    }
+
+
+    static void printArray(int[] ar) {
+        for (int n : ar) {
+            System.out.print(n + " ");
+        }
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int[] ar = new int[n];
+        for (int i = 0; i < n; i++) {
+            ar[i] = in.nextInt();
+        }
+        insertionSort(ar);
+    }
+}

src/com/hackerrank/algorithms/arraysandsorting/QuickSort1.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/2/15
+ * Time: 5:13 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class QuickSort1 {
+
+    static void partition(int[] ar) {
+        int pivot = ar[0], j = 0;
+        int[] arCopy = ar.clone();
+
+        for (int i = 0; i < arCopy.length; i++) {
+            if (arCopy[i] < pivot) ar[j++] = arCopy[i];
+        }
+        for (int i = 0; i < arCopy.length; i++) {
+            if (arCopy[i] >= pivot) ar[j++] = arCopy[i];
+        }
+        printArray(ar);
+    }
+
+    static void printArray(int[] ar) {
+        for (int n : ar) {
+            System.out.print(n + " ");
+        }
+        System.out.println("");
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int[] ar = new int[n];
+        for (int i = 0; i < n; i++) {
+            ar[i] = in.nextInt();
+        }
+        partition(ar);
+    }
+}

src/com/hackerrank/algorithms/arraysandsorting/QuickSort2.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/3/15
+ * Time: 1:05 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class QuickSort2 {
+
+    static void quickSort(int[] ar, int start, int end) {
+        int pivot = ar[0];
+        List<Integer> ar1 = new ArrayList<>();
+        List<Integer> ar2 = new ArrayList<>();
+
+        for (int i = start; i < end; i++) {
+            if (ar[i] < pivot) {
+                ar1.add(ar[i]);
+            } else if (ar[i] > pivot) {
+                ar2.add(ar[i]);
+            }
+        }
+
+        //TODO
+    }
+
+    static void printArray(int[] ar) {
+        for (int n : ar) {
+            System.out.print(n + " ");
+        }
+        System.out.println("");
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int n = in.nextInt();
+        int[] ar = new int[n];
+        for (int i = 0; i < n; i++) {
+            ar[i] = in.nextInt();
+        }
+        quickSort(ar, 0, ar.length);
+    }
+}

src/com/hackerrank/algorithms/arraysandsorting/RunningTime.java

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+package me.ramswaroop.algorithms.arraysandsorting;
+
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ * User: ramswaroop
+ * Date: 3/2/15
+ * Time: 5:02 PM
+ * To change this template go to Preferences | IDE Settings | File and Code Templates
+ */
+public class RunningTime {
+    static void insertionSortPart2(int[] ar) {
+        int c = 0;
+        for (int i = 1; i < ar.length; i++) {
+            int V = ar[i], j;
+            for (j = i - 1; j >= 0 && ar[j] > V; j--, c++) {
+                ar[j + 1] = ar[j];
+            }
+            ar[j + 1] = V;
+            //printArray(ar);
+        }
+        System.out.print(c);
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int s = in.nextInt();
+        int[] ar = new int[s];
+        for (int i = 0; i < s; i++) {
+            ar[i] = in.nextInt();
+        }
+        insertionSortPart2(ar);
+
+    }
+
+    private static void printArray(int[] ar) {
+        for (int n : ar) {
+            System.out.print(n + " ");
+        }
+        System.out.println("");
+    }
+}

src/com/hackerrank/algorithms/strings/AlternatingCharacters.java

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+package me.ramswaroop.algorithms.strings;
+
+import java.util.Scanner;
+
+/**
+ * Created by IntelliJ IDEA.
+ *
+ * @author: ramswaroop
+ * @date: 10/22/15
+ * @time: 9:24 AM
+ */
+public class AlternatingCharacters {
+
+    public static int countDeletions(String s) {
+        int count = 0, index = 0;
+        for (int i = 1; i < s.length(); i++) {
+            if (s.charAt(i) == s.charAt(index)) {
+                count++;
+            } else {
+                index = i;
+            }
+        }
+        return count;
+    }
+
+    public static void main(String[] args) {
+        Scanner in = new Scanner(System.in);
+        int t = Integer.parseInt(in.nextLine());
+        String[] input = new String[t];
+        for (int i = 0; i < t; i++) {
+            input[i] = in.nextLine();
+        }
+        for (int i = 0; i < t; i++) {
+            System.out.println(countDeletions(input[i]));
+        }
+    }
+}