Added sorting problems

Author: Prashant Jain

src/in/knowledgegate/dsa/sorting/algos/InsertionSort.java

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+package in.knowledgegate.dsa.sorting.algos;
+
+/**
+ * Implement a sorting algo for Insertion Sort
+ */
+public class InsertionSort implements SortingAlgo {
+  @Override
+  public void sort(int[] nums) {
+    for (int i = 1; i < nums.length; i++) {
+      int key = nums[i];
+      int j = i - 1;
+      while (j >= 0 && nums[j] > key) {
+        nums[j+1] = nums[j];
+        j--;
+      }
+      nums[j+1] = key;
+    }
+  }
+}

src/in/knowledgegate/dsa/sorting/algos/SortingAlgo.java

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+package in.knowledgegate.dsa.sorting.algos;
+
+public interface SortingAlgo {
+  void sort(int[] nums);
+}

src/in/knowledgegate/dsa/sorting/problems/SquaresOfSortedArray.java

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+package in.knowledgegate.dsa.sorting.problems;
+
+/**
+ * Given an integer array nums sorted in
+ * non-decreasing order, return an array of the
+ * squares of each number sorted in non-decreasing
+ * order.
+ *
+ * Example 1:
+ * Input: nums = [-4,-1,0,3,10]
+ * Output: [0,1,9,16,100]
+ * Explanation: After squaring, the array becomes
+ * [16,1,0,9,100].
+ * After sorting, it becomes [0,1,9,16,100].
+ *
+ * Example 2:
+ * Input: nums = [-7,-3,2,3,11]
+ * Output: [4,9,9,49,121]
+ *
+ *
+ * Constraints:
+ * 1 <= nums.length <= 104
+ * -104 <= nums[i] <= 104
+ * nums is sorted in non-decreasing order.
+ */
+public class SquaresOfSortedArray {
+  public int[] sortedSquares(int[] nums) {
+    int beg = 0, end = nums.length - 1;
+    int[] result = new int[nums.length];
+    for (int i = 0; i < nums.length; i++) {
+      int sq1 = (int) Math.pow(nums[beg], 2);
+      int sq2 = (int) Math.pow(nums[end], 2);
+      if (sq1 >= sq2) {
+        result[nums.length - 1 - i] = sq1;
+        beg++;
+      } else {
+        result[nums.length - 1 - i] = sq2;
+        end--;
+      }
+    }
+    return result;
+  }
+}