Added SaddlebackSearch

Author: NISHITA97

Searches/SaddlebackSearch.java

@@ -0,0 +1,84 @@
+import java.util.*;
+
+/**
+ * Program to perform Saddleback Search
+ * Given a sorted 2D array(elements are sorted across every row and column, assuming ascending order)
+ * of size n*m we can search a given element in O(n+m) 
+ * 
+ * we start from bottom left corner
+ * if the current element is greater than the given element then we move up
+ * else we move right
+ * Sample Input:
+ * 5 5 ->Dimensions
+ * -10 -5 -3 4 9
+ * -6 -2 0 5 10
+ * -4 -1 1 6 12
+ * 2 3 7 8 13
+ * 100 120 130 140 150
+ * 140 ->element to be searched
+ * output: 4 3 // first value is row, second one is column
+ * 
+ * @author Nishita Aggarwal
+ *
+ */
+
+public class SaddlebackSearch {
+	
+	/**
+	* This method performs Saddleback Search
+	* 
+     	* @param arr The **Sorted** array in which we will search the element.
+	* @param crow the current row.
+     	* @param ccol the current column.
+	* @param ele the element that we want to search for.
+     	* 
+	* @return The index(row and column) of the element if found.
+     	* Else returns -1 -1.
+     	*/
+	static int[] search(int arr[][],int crow,int ccol,int ele){
+		
+		//array to store the answer row and column
+		int ans[]={-1,-1};
+		if(crow<0 || ccol>=arr[crow].length){
+			return ans;
+		}
+		if(arr[crow][ccol]==ele)
+		{
+			ans[0]=crow;
+			ans[1]=ccol;
+			return ans;
+		}
+		//if the current element is greater than the given element then we move up
+		else if(arr[crow][ccol]>ele)
+		{
+			return search(arr,crow-1,ccol,ele);
+		}
+		//else we move right
+		return search(arr,crow,ccol+1,ele);
+	}
+	
+	/**
+	 * Main method
+	 * 
+	 * @param args Command line arguments
+	 */
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		Scanner sc=new Scanner(System.in);
+		int arr[][];
+		int i,j,rows=sc.nextInt(),col=sc.nextInt();
+		arr=new int[rows][col];
+		for(i=0;i<rows;i++)
+		{
+			for(j=0;j<col;j++){
+				arr[i][j]=sc.nextInt();
+			}
+		}
+		int ele=sc.nextInt();
+		//we start from bottom left corner
+		int ans[]=search(arr,rows-1,0,ele);
+		System.out.println(ans[0]+" "+ans[1]);
+		sc.close();
+	}
+
+}