Add algorithm to search for an element in 2D array (#3306)

src/main/java/com/thealgorithms/searches/RowColumnWiseSorted2dArrayBinarySearch.java

@@ -0,0 +1,37 @@
+package com.thealgorithms.searches;
+
+// The search is for any array which is sorted row and column-wise too. For ex :
+// int[][] arr = { {10, 20, 30, 40},
+//                 {15, 25, 35, 45},
+//                 {18, 28, 38, 48},
+//                 {21, 31, 41, 51}
+//                };
+// This array is sorted in both row and column manner.
+// In this two pointers are taken, the first points to the 0th row and the second one points to end column, and then the
+// element corresponding to the pointers placed in the array is compared with the target that either its equal, greater or
+// smaller than the target. If the element is equal to the target, the co-ordinates of that element is returned i.e. an
+// array of the two pointers will be returned, else if the target is greater than corresponding element then the pointer
+// pointing to the 0th row will be incremented by 1, else if the target is lesser than the corresponding element then the
+// pointer pointing to the end column will be decremented by 1. And if the element doesn't exist in the array, an array
+// {-1, -1} will be returned.
+
+public class RowColumnWiseSorted2dArrayBinarySearch {
+
+    public static int[] search(int[][] matrix, int target) {
+
+        int rowPointer = 0;                 //The pointer at 0th row
+        int colPointer = matrix.length-1;   //The pointer at end column
+
+        while (rowPointer < matrix.length && colPointer >= 0){
+
+            if (matrix[rowPointer][colPointer] == target)
+                return new int[] {rowPointer, colPointer};
+
+            else if (matrix[rowPointer][colPointer] < target)
+                rowPointer++;               //Incrementing the row pointer if the target is greater
+            else
+                colPointer--;               //Decrementing the column pointer if the target is lesser
+        }
+        return new int[] {-1, -1};          //The not found condition
+    }
+}