package Searches; import java.util.Scanner; /** * 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 row the current row. * @param col the current column. * @param key the element that we want to search for. * @return The index(row and column) of the element if found. * Else returns -1 -1. */ private static int[] find(int arr[][], int row, int col, int key) { //array to store the answer row and column int ans[] = {-1, -1}; if (row < 0 || col >= arr[row].length) { return ans; } if (arr[row][col] == key) { ans[0] = row; ans[1] = col; return ans; } //if the current element is greater than the given element then we move up else if (arr[row][col] > key) { return find(arr, row - 1, col, key); } //else we move right return find(arr, row, col + 1, key); } /** * 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[] = find(arr, rows - 1, 0, ele); System.out.println(ans[0] + " " + ans[1]); sc.close(); } }