Search a sorted matrix

Given a sorted matrix where rows and the columns are sorted. Write an algorithm to search an element in the matrix in O(n).


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Algorithm Visualization




Code Snippet

			
package com.ideserve.virendra.questions;

public class SortedMatrix {
	
public static boolean stairSearch(int matrix[][], int n, int element) {
  if (element < matrix[0][0] || element > matrix[n-1][n-1]) 
	  return false;
  int r = 0; // row
  int c = n-1;// column
  while (r <= n-1 && c >= 0) {
    if (matrix[r][c] < element) 
      r++;
    else if (matrix[r][c] > element)
      c--;
    else
      return true;
  }
  return false;
}

public static void main(String args[])
{
	int[][] mat =  {   { 2, 6, 7, 11},
					   { 3, 8, 10, 12},
					   { 4, 9, 11, 13},
					   { 5, 15, 16, 18}
					   };
	
	System.out.println(stairSearch(mat, 4, 9));
	
}

}
		

Order of the Algorithm

Time Complexity is O(n)
Space Complexity is O(1)


Contribution

  • Sincere thanks from IDeserve community to Virendra Karappa for compiling current post.

    Virendra Karappa

    Ninja Programmer