# prepinsta top 100 codes

Below You will find some of the most important codes in languages like C, C++ and Java. These codes are of prime importance for college semester exams and also for various online tests and interviews of the companies offering placements within varying range in LPA.

These codes are very important since these will help you clear your basic concepts in various languages.

## Codes for Recursion

• Power of a Number – C | C++ | Java | Python
• Prime Number – C | C++ | Java | Python
• Largest element in an array – C | C++ | Java | Python
• Smallest element in an array – C | C++ | Java | Python
• Reversing a Number – C | C++ | Java | Python
• HCF of two numbers – C | C++ | Java | Python
• LCM of two numbers – C | C++ | Java | Python
• Program to calculate length of the string using recursion- C | C++ | Java | Python
• Print All Permutations of a String- C | C++ | Java | Python
• Given an integer N the task is to print the F(N)th term.- C | C++ | Java | Python
• Given a list arr of N integers, print sums of all subsets in it- C | C++ | Java | Python
• Last non-zero digit in factorial- C | C++ | Java | Python
• Given a positive integer N, return the Nth row of pascal’s triangle – C | C++ | Java | Python
• Given an integer N representing the number of pairs of parentheses, the task is to generate all combinations of well-formed(balanced) parentheses – C | C++ | Java | Python
• Find the Factorial of a number using recursion – C | C++ | Java | Python
• Find all possible Palindromic partitions of the given String – C | C++ | Java | Python
• Find all the N bit binary numbers having more than or equal 1’s than 0’s – C | C++ | Java | Python
• Given a set of positive integers, find all its subsets – C | C++ | Java | Python
• Given a string s, remove all its adjacent duplicate characters recursively – C | C++ | Java | Python

## Important Codes related to Arrays

• Find Largest element in an array : C | C++ | Java | Python
• Find Smallest Element in an Array : C | C++ | Java | Python
• Find the Smallest and largest element in an array : C | C++ | Java | Python
• Find Second Smallest Element in an Array : C | C++ | Java | Python
• Calculate the sum of elements in an array : C | C++ | Java | Python
• Reverse an Array : C | C++ | Java | Python
• Sort first half in ascending order and second half in descending : C | C++ | Java | Python
• Sort the elements of an array : C | C++ | Java | Python
• Finding the frequency of elements in an array : C | C++ | Java | Python
• Sorting elements of an array by frequency : C | C++ | Java | Python
• Finding the Longest Palindrome in an Array : C | C++ | JavaPython
• Counting Distinct Elements in an Array : C | C++ | JavaPython
• Finding  Repeating elements in an Array : C++ | Java | Python
• Finding Non Repeating elements in an Array : C | C++ | Java | Python
• Removing Duplicate elements from an array : C | C++ | Java | Python
• Finding Minimum scalar product of two vectors : C | C++ | Java | Python
• Finding Maximum scalar product of two vectors in an array : C | C++ | Java | Python
• Counting the number of even and odd elements in an array : C | C++ | Java | Python
• Find all Symmetric pairs in an array : C | C++ | Java | Python
• Find maximum product sub-array in a given array : C | C++ | Java | Python
• Finding Arrays are disjoint or not : C | C++ | Java | Python
• Determine Array is a subset of another array or not : C | C++ | Java | Python
• Determine can all numbers of an array be made equal : C | C++ | Java | Python
• Finding Minimum sum of absolute difference of given array : C | C++ | Java | Python
• Sort an array according to the order defined by another array : C | C++ | Java | Python
• Replace each element of the array by its rank in the array : C | C++ | Java | Python
• Finding equilibrium index of an array : C | C++ | JavaPython
• Rotation of elements of array- left and right : C | C++ | JavaPython
• Block swap algorithm for array rotation : C | C++ | JavaPython
• Juggling algorithm for array rotation : C | C++ | Java | Python
• Finding Circular rotation of an array by K positions : C | C++ | Java | Python
• Balanced Parenthesis Problem : C | C++ | Java | Python

## Operations on Strings

• Check whether a character is a vowel or consonant : C | C++ | Java | Python
• Check whether a character is a alphabet or not : C | C++ | Java | Python
• Find the ASCII value of a character : C | C++ | Java | Python
• Length of the string without using strlen() function : C | C++ | Java | Python
• Toggle each character in a string : C | C++ | Java | Python
• Count the number of vowels : C | C++ | Java | Python
• Remove the vowels from a String : C | C++ | Java | Python
• Check if the given string is Palindrome or not : C | C++ | Java | Python
• Print the given string in reverse order : C | C++ | Java | Python
• Remove all characters from string except alphabets : C | C++ | Java | Python
• Remove spaces from a string : C | C++ | Java | Python
• Remove brackets from an algebraic expression : C | C++ | Java | Python
• Count the sum of numbers in a string : C | C++ | Java | Python
• Capitalize the first and last character of each word of a string : C | C++ | Java | Python
• Calculate frequency of characters in a string : C | C++ | Java | Python
• Find non-repeating characters in a string : C | C++ | JAVA | Python
• Check if two strings are Anagram or not : C | C++ | Java | Python
• Replace a sub-string in a string: C | C++ | Java | Python
• Replacing a particular word with another word in a string – C | C++ | Java | Python
• Count common sub-sequence in two strings : C | C++ | Java | Python
• Check if two strings match where one string contains wildcard characters : C | C++ | Java | Python
• Print all permutations of a given string in lexicographically sorted order : C | C++ | Java | Python

## Advanced Codes related to Arrays

• Given an array which consists of only 0, 1 and 2. Sort the array without using any  algorithm – C | C++ | Java | Python
• Find the “Kth” max and min element of an array – C | C++ | Java | Python
• Move all the negative elements to one side of the array – C | C++ | Java | Python
• Find the Union and Intersection of the two sorted arrays. – C | C++ | Java | Python
• Find Largest sum contiguous Subarray – C | C++ | Java | Python
• Minimize the maximum difference between heights – C | C++ | Java | Python
• Minimum no. of Jumps to reach the end of an array – C | C++ | Java | Python
• Find duplicate in an array of N+1 Integers – C | C++ | Java | Python
• Merge 2 sorted arrays without using extra space. – C | C++ | Java | Python
• Kadane’s Algorithm – C | C++ | Java | Python
• Merge Intervals – C | C++ | Java | Python
• Count Inversion – C | C++ | Java | Python
• Best time to buy and Sell stock – C | C++ | Java | Python
• Find all pairs on integer array whose sum is equal to given number – C | C++ | Java | Python
• Find if there is any subarray with sum equal to 0 – C | C++ | Java | Python
• Find factorial of a Large Number – C | C++ | Java | Python
• Find common elements In 3 sorted arrays – C | C++ | Java | Python
• Rearrange the array in alternating positive and negative items with O(1) extra space – C | C++ | Java | Python
• Given an array of size n and a number k, find all elements that appear more than ” n/k ” times. – C | C++ | Java | Python
• Maximum profit by buying and selling a share atmost twice – C | C++ | Java | Python
• Next Permutation – C | C++ | Java | Python
• Find longest consecutive subsequence – C | C++ | Java | Python
• Trapping Rain water problem – C | C++ | Java | Python
• Chocolate Distribution problem – C | C++ | Java | Python
• Smallest Subarray with sum greater than a given value – C | C++ | Java | Python
• Three way partitioning of an array around a given value – C | C++ | Java | Python
• Minimum no. of operations required to make an array palindrome – C | C++ | Java | Python
• Median of 2 sorted arrays of equal size – C | C++ | Java | Python
• Median of 2 sorted arrays of different size – C | C++ | Java | Python

## Codes related to Matrix

• Spiral traversal on a Matrix – C | C++ | Java | Python
• Search an element in a matrix – C | C++ | Java | Python
• Find median in a row wise sorted matrix – C | C++ | Java | Python
• Find row with maximum no. of 1’s – C | C++ | Java | Python
• Print elements in sorted order using row-column wise sorted matrix – C | C++ | Java | Python
• Find a specific pair in matrix – C | C++ | Java | Python
• Rotate matrix by 90 degrees – C | C++ | Java | Python
• Kth smallest element in a row-column wise sorted matrix – C | C++ | Java | Python
• Common elements in all rows of a given matrix – C | C++ | Java | Python

## Pattern Printing

```           ****
****
****
****
```

Square Star Pattern

Difficulty – ★

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```           ****
*  *
*  *
****
```

Hollow Square Star Pattern

Difficulty – ★ and 1/2

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```           ****
****
****
****
```

Rhombus Star Pattern

Difficulty – ★★

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```           ******
******
******
******
```

Rectangle Star Pattern

Difficulty – ★

Checkout code for this program –

```           ******
*    *
*    *
******
```

Hollow Rectangle Star Pattern

Difficulty – ★ and 1/2

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```           ******
******
******
******
```

Parallelogram Star Pattern

Difficulty – ★★

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```           ****
****
****
****
```

Mirrored Rhombus Star Pattern

Difficulty – ★★ and 1/2

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```           *
**
***
****
```

Triangle Star Pattern

Difficulty – ★ and 1/2

```              *
***
*****
*******```

Pyramid Star Pattern

Difficulty – ★★

```              *
* *
*   *
*******```

Hollow Pyramid Star Pattern

Difficulty – ★★

```           *******
*****
***
*```

Inverted Pyramid Star Pattern

Difficulty – ★★

```           *******
*   *
* *
*```

Inverted Hollow Pyramid Star Pattern

Difficulty – ★★ and 1/2

```           *
**
***
****
***
**
*```

Half Diamond Star Pattern

```              *
**
***
****
***
**
*```

Half Diamond Star Pattern Inverted

```             *
***
*****
*******
*****
***
*```

Diamond Star Pattern

## Number Pattern Printing Programs

```           1111
1111
1111
1111```

Basic Square 1 Pattern

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```           1111
2222
3333
4444```

Basic Square incrementing Pattern

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```           333
313
323
333```

Internal varsity square Pattern

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```           1
23
456
78910```

Basic Right Triangle Number Pattern

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```           10987
456
32
1```

Basic Right Triangle Number Pattern (Inverted)

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```           6666
555
44
3```

Basic incrementing Triangle Pattern initialised = 3

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```           3
44
555
6666```

Basic incrementing Triangle Pattern(Inverted) initialised = 3 Checkout code for this program –

```           3
4 5
6 7 8
9 10 11 12```

Basic double incrementing Triangle Pattern initialised = 3 Checkout code for this program –

```           3
44
555
6666
555
44
3```

Basic incrementing Diamond Pattern(Inverted) initialised = 3

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```            3
45
678
9101112
678
45
3```

Basic double incrementing Triangle Pattern initialised = 3

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```           3
54
876
1211109
876
54
3```

Basic incrementing Triangle Pattern(Inverted) initialised Mirrored = 3

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```           2
33
444
5555
5555
444
33
2```

Basic incrementing Diamond Pattern(Inverted Sandwich) initialised = 3

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```            2
34
567
891011
891011
567
34
2```

Basic double incrementing Triangle Pattern initialised Sandwich= 3

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```           2
43
765
1110198
1110198
765
43
2```

Basic incrementing Triangle Pattern(Inverted) initialised Mirrored Sandwich = 3

Checkout code for this program –

## Number Star Mix Pattern

```           1*2*3*4
5*6*7*8
9*10*11*12
13*14*15*16```

Basic incrementing Squared Number-Star Pattern

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C | Java | Python

```           13*14*15*16
9*10*11*12
5*6*7*8
1*2*3*4```

Basic incrementing inverted Squared Number-Star Pattern

Checkout code for this program

C | Java | Python

```          1*2*3*4
9*10*11*12
5*6*7*8
13*14*15*16```

Basic incrementing Squared Number-Star Pattern + Basic incrementing inverted Squared Number-Star Pattern (alternate)

Checkout code for this program

C | Java | Python

```          1*2*3*4
9*10*11*12
13*14*15*16
5*6*7*8```

Basic incrementing Squared Number-Star Pattern + Basic incrementing inverted Squared Number-Star Pattern (alternate)

Type 2

Checkout code for this program

C | Java | Python

```          1*2*3*4
9*10*11*12
17*18*19*20
13*14*15*16
5*6*7*8```

Basic incrementing Squared Number-Star Pattern + Basic incrementing inverted Squared Number-Star Pattern (alternate)

Type 3

Checkout code for this program

C | Java | Python

```          4*3*2*1
12*11*10*9
8*7*6*5
16*15*14*13```

Basic incrementing Squared Number-Star Pattern Mirrored + Basic incrementing inverted Squared Number-Star Pattern Mirrored (alternate)

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C | Java | Python

```           1
2*3
4*5*6
7*8*9*10```

Basic incrementing Triangle Pattern

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C | Java | Python

```           7*8*9*10
4*5*6
2*3
1```

Basic incrementing Triangle Pattern

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C | Java | Python

```           1
4*5*6
2*3
7*8*9*10```

Basic incrementing Triangle Pattern + Inverted (Mix)

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C | Java | Python

```           1
3*2
6*5*4
10*9*8*7```

Basic incrementing mirrored Triangle Pattern

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C | Java | Python

```           10*9*8*7
6*5*4
3*2
1```

Basic incrementing inverted mirrored Triangle Pattern

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C | Java | Python

```           1
4*5*6
2*3
7*8*9*10```

Basic incrementing Triangle Pattern + Inverted (Mix)

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C | Java | Python

```           1
2*2
3*3*3
4*4*4*4
3*3*3
2*2
1```

Basic Diamond Number Star Pattern

Checkout code for this program

C | Java | Python

```           1
2*2
3*3*3
4*4*4*4
4*4*4*4
3*3*3
2*2
1```

Basic Diamond Number Star Pattern (Sandwich)

Checkout code for this program

C | Java | Python

```           4*4*4*4
3*3*3
2*2
1
1
2*2
3*3*3
4*4*4*4```

Basic Diamond Number Star Pattern (Sandwich Inverted)

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C | Java | Python

```           2
3*3
4*4*4
3*3
2```

Basic Diamond Number Star Pattern initialised

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C | Java | Python

```           2
3*3
4*4*4
4*4*4
3*3
2```

Basic Diamond Number Star Pattern (Sandwich)

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C | Java | Python

```           6*6*6*6
5*5*5
4*4
3
3
4*4
5*5*5
6*6*6*6```

Basic Diamond Number Star Pattern (Sandwich Inverted)

Checkout code for this program

C | Java | Python

### Few more pattern programs

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