70 lines
2.1 KiB
Java
70 lines
2.1 KiB
Java
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)
|
|
*
|
|
* <p>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();
|
|
}
|
|
}
|