Java/Searches/SaddlebackSearch.java at master · rcfgnu/Java · GitHub

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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();

}

Java/Searches/SaddlebackSearch.java at master · rcfgnu/Java · GitHub

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