Ekiras Blogs: Algorithms

Arrays : Finding the Element in array where next element is +1, +0 or -1

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Problem Statement

You are given an array where each element follows the rule that given any index, the number at that index will either be

+1 of the number at that index.
+0 of the number at that index.
-1 of the number at that index.

Suppose the array is

Sample Input

arr = {1,2,3,2,3,4,5,6,7,6,5,4,5,6,4,4,4,4};

search = 5

Sample Output

6 (First occurrence of search )

Sample Input

arr = {1,2,1,2,1,2,1,2,1,2};

search = 5

Sample Output

1 ( Element is not found in the array)

Algorithm

Star iterating from start of the array.
Check if the value at the index is same as the search value

if yes, then return the index
if no, then increment the index counter by modulus of difference of value to search and value at index

return -1 if value to search does not exist in the array.

Java Program

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package com.ekiras.arrays;
public class SearchElement {
private static final int[] arr = {1,2,3,2,3,4,5,6,7,6,5,4,5,6,4,4,4,4};
public static void main(String args[]){
System.out.println("elemet found at :: " + find(5) + "th index");
}
public static int find(int search){
int cntr=0;
while(cntr<arr.length){
if(arr[cntr]==search)
return cntr;
else{
cntr += Math.abs(search - arr[cntr]);
}
}
return -1;
}
}

package com.ekiras.arrays;

public class SearchElement {

 private static final int[] arr = {1,2,3,2,3,4,5,6,7,6,5,4,5,6,4,4,4,4};
 
 public static void main(String args[]){
  System.out.println("elemet found at :: " + find(5) + "th index");
  
 }
 
 public static int find(int search){
  int cntr=0;
  while(cntr<arr.length){
   if(arr[cntr]==search)
    return cntr;
   else{
    cntr += Math.abs(search - arr[cntr]);
   }
  }
  return -1;
 }
 
}

Ekiras Blogs

Arrays : Finding the Element in array where next element is +1, +0 or -1

Problem Statement

Sample Input

Sample Output

Sample Input

Sample Output

Algorithm

Java Program

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