This document discusses array operations in Java, including inserting and deleting values from arrays. It provides code examples for inserting a value at a specific index or suitable position, and for deleting a value by index or value. The time complexity of these operations is analyzed, with inserting and deleting from an array both having linear time complexity of O(n) due to potential array shifting. Examples of edge cases like all values being smaller than a new insert value are also discussed.

1. using Java
2015
Data Structure
Prepared by: Mahmoud Rafeek Al-farra
in Java
3. Array Operations

2. mfarra.cst.ps www.fb.com/MahmoudRFarra
Contents
Complexity
Insert in array (index, in order)
Delete from array (index, value)
Revision

3. Introduction
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Array’s
Operations
Insert
At suitable
position
At index
Delete
Specific
value
Value of
index

4. Insert value at index
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2 7 80 88 90 999 12 15 23 30 45 70 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0
13
14
To insert value at index 4 (5’th position)
2 7 80 88 90 999 12 15 23 30 45 70 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0 14
13

5. Insert value at index
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1. public void insertValue(int[] arr, int value, int index)
2. {
3. for (int i = arr.Length - 1; i > index; i--)
4. arr[i] = arr[i - 1];
5. arr[index] = value;
6. }
In the previous code:
if the loop start from the wanted index up to the length of array,
a logical error will be appeared, (What is it ?)

6. Insert value at suitable position
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2 7 80 88 90 999 12 15 23 30 45 70 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0
15
14
To insert the value at suitable position (in order)
2 7 80 88 90 999 12 15 23 30 45 15 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0 14
1 2 3 4 5 6 7 8 9 9
array
0
2 7 80 88 90 999 12 23 30 45 15 77
1 2 3 4 5 6 7 8 9 10 11 12 13
99
14
Null
1. Search for the index of value 15.
2. Shift the value to the left (to free the wanted position)
3. Insert the new value (15)

7. Insert value at suitable position
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1. public void insertValueInOrder(int[] arr, int value)
2. {
3. // to find the position of value
4. int i;
5. for ( i = 0; i < arr.Length-1; i++)
6. {
7. if (id[i] > value)
8. {
9. break;
10. }
11. }
12. // shift value to free wanted position
13. for (int j = arr.Length - 1; j > i; j--)
14. arr[j] = arr[j - 1];
15. arr[i] = value;
16. }
Self Study:
What about, if
all the values in
array is smaller
than the new
value?

8. Delete value from index
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2 7 80 88 90 999 12 15 23 30 45 70 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0
15
14
To delete the value of 5’th cell
2 7 80 88 90 999 12 15 23 30 45 15 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0 14
1 2 3 4 5 6 7 8 9 9
array
0
2 7 80 88 90 999 12 23 30 45 15 77
1 2 3 4 5 6 7 8 9 10 11 12 13
99
14
Null

9. Delete value from index
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1. public void deleteValue(int[] arr, int index)
2. {
3. // overwrite on position of value
4. for (int k =index ; k < id.Length-1; k++)
5. id[k] = id[k + 1];
6. }

10. To delete the value
1. Search for the index of value 15.
2. Overwrite on the index of value from it the last position.
Delete value
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2 7 80 88 90 999 12 15 23 30 45 70 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0
15
14
2 7 80 88 90 999 12 15 23 30 45 15 77
1 2 3 4 5 6 7 8 9 10 11 12 13
array
0 14
1 2 3 4 5 6 7 8 9 9
array
0
2 7 80 88 90 999 12 23 30 45 15 77
1 2 3 4 5 6 7 8 9 10 11 12 13
99
14
Null

11. Delete value
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1. public void deleteValue(int[] arr, int value)
2. {
3. // to find the position of value
4. int i;
5. for ( i = 0; i < arr.Length-1; i++)
6. {
7. if (id[i] == 12)
8. {
9. break;
10. }
11. }
12. // overwrite on position of value
13. for (int k =i ; k< id.Length-1; k++)
14. id[k] = id[k + 1];
15. }
Self Study:
What is the
result, if the
wanted value
does not found
in array ?

12. Time Complexity
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 To insert on value in specific index in array with size
(n), we need to shift all values of array (worst state),
this mean the time complexity is O(n).
 What about delete ?

13. Time Complexity
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 To insert on value in suitable index in array with size
(n), we need to:
1. Search for the suitable position by linear approach
(O(n)).
2. Shift all values of array (worst state), this mean the
time complexity is O(n).
 The total complexity O(2n).
 What about delete ?

14. using Java
2015
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