Refresher : Patterns¶

Question 1¶

Given N as input, print * N times.

TestCase¶

Input¶

Output¶

* * * * *

PseudoCode¶

function pattern(int N) {
    for (int i = 1; i <= N; i++) {
        system.out.print(' * ');
    }
}

Question 2¶

Given N as input. Print a square of size N * N containing * in each cell.

TestCase¶

Input¶

Output¶

* * * * *
* * * * *
* * * * *
* * * * *
* * * * *

PseudoCode¶

function pattern(int N){
    for(int i = 1 ; i <= N ; i ++ ){
        for(int j = 1 ; j <= N ; j ++ ){
            system.out.print(' * ');
        }
        system.out.println();
    }
}

Question 3¶

Given N,M as input, print a rectangle of size N * M containing * in each cell.

TestCase¶

Input¶

N = 3
M = 4

Output¶

* * * * 
* * * *
* * * *

PseudoCode¶

function pattern(int N,int M){
    for(int i = 1 ; i <= N ; i ++ ){
        for(int j = 1 ; j <= M ; j ++ ){
            system.out.print(' * ');
        }
        system.out.println();
    }
}

Question 4¶

Given N as input, print a staircase pattern of size N.

TestCase¶

Input¶

Output¶

*
* *
* * *
* * * *
* * * * *

Observation¶

The key observation here is that:

The staircase pattern formed the right-angled triangle.
The number of stars in each row is equal to the row number.

Row	Stars
1	1
2	2
3	3
4	4

PseudoCode¶

function pattern(int N){
    for(int i = 1 ; i <= N ; i ++ ){
        for(int j = 1 ; j <= i ; j ++ ){
            system.out.print(' * ');
        }
        system.out.println();
    }
}

Question 5¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 3

Output 1¶

*
* 2
* 2 *

Input 2¶

N = 4

Output 2¶

*
* 2
* 2 *
* 2 * 4

Observation¶

The key observations are:

For even column numbers, print *.
For odd column numbers, print the column number.

PseudoCode¶

function pattern(int N){
    for(int i = 1 ; i <= N ; i ++ ){
        for(int j = 1 ; j <= i ; j ++ ){
            if(j % 2 == 1) system.out.print(' * ');
            else system.out.print(j);
        }
        system.out.println();
    }
}

Question 6¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 3

Output 1¶

* _ *
* _ *
* _ *

Input 2¶

N = 4

Output 2¶

* _ _ *
* _ _ *
* _ _ *
* _ _ *

Observation¶

The key observation here is that:

The first and last column number of each row is * .
There are total (N - 2) spaces in between stars( * ).

PseudoCode¶

function pattern(int N){
    for(int i = 1 ; i <= N ; i ++ ){
        system.out.print(' * ');
        for(int j = 2 ; j <= N - 1 ; j ++ ){
            system.out.print('_');
        }
        system.out.print(' * ');
        system.out.println();
    }
}

Question 7¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 3

Output 1¶

* * * 
* *
*

Input 2¶

N = 4

Output 2¶

* * * *
* * *
* *
*

Observation¶

As shown in above, the number of stars in each row is one less than the previous row except 1^st row where number of stars is N. Hence, we can derive the formula:

Number of stars in each row is equal to the (N - rowNumber + 1).

For N = 4,

Row	Stars
1	4
2	3
3	2
4	1

PseudoCode¶

function pattern(int N){
    for(int i = 1 ; i <= N ; i ++ ){
        for(int j = i ; j <= N ; j ++ ){
            system.out.print(' * ');
        }
        system.out.println();
    }
}

Question 8¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 3

Output 1¶

*   *
*  *
* *

Input 2¶

N = 4

Output 2¶

*     *
*   *
*  *
* *

Observation¶

The key observation here is that:

The first and last character of each row is ' * '.
Number of spaces in each row is one less than the previous row except first row where number of spaces between stars is N - 1. Hence we can say that there are total (N - rowNumber) spaces in between stars( * ).

For N = 4,

Row	Total number of spaces between stars
1	3
2	2
3	1
4	0

PseudoCode¶

function pattern(int N) {
    for (int i = 1; i <= N; i++) {
        system.out.print(' * ');
        for (int j = 1; j <= N - i; j++) {
            system.out.print(' ');
        }
        system.out.print(' * ');
        system.out.println();
    }
}

Question 9¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 3

Output 1¶

    *
  * *
* * *

Input 2¶

N = 4

Output 2¶

      *
    * *
  * * *
* * * *

Observation¶

The key observation here is that:

Number of spaces in each row is one less than the previous row except 1^st row where number of spaces are N - 1. Hence we can say that there are total (N - rowNumber) spaces in the starting of each row.
Number of sars in each row is one more than the previous row except 1^st row where number of stars are 1. Hence we can say that there are total (rowNumber) stars at the last of each row.

For N = 4,

Row	Total number of spaces	Total number of stars
1	3	1
2	2	2
3	1	3
4	0	4

PseudoCode¶

function pattern(int N) {
    for (int i = 1; i <= N; i++) {
        for (int j = 1; j <= N - i; j++) {
            system.out.print(' ');
        }
        for (int j = 1; j <= i; j++) {
            system.out.print(' * ');
        }
        system.out.println();
    }
}

¶

Question 10¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 4

Output 1¶

********
***  ***
**    **
*      *

Observation¶

The key observation here is that:

There are total (N - rowNumber + 1) stars in the begining and end of each row.
There are total ((rowNumber - 1) * 2) spaces between these stars.

For N = 4,

Row	Stars	Spaces	Stars
1	4	0	4
2	3	2	3
3	2	4	2
4	1	6	1

PseudoCode¶

function pattern(int N) {
    for (int i = 1; i <= N; i++) {
        for (int j = 1; j <= N - i + 1; j++) {
            system.out.print(' * ');
        }
        for (int j = 1; j <= (i - 1) * 2; j++) {
            system.out.print(' ');
        }
        for (int j = 1; j <= N - i + 1; j++) {
            system.out.print(' * ');
        }
        system.out.println();
    }
}

Question 11¶

Given N as input, print the pattern as shown below.

TestCase¶

Input 1¶

N = 4

Output 1¶

   *
  ***
 *****
*******

Observation¶

The key observation here is that:

Number of spaces in each row is one less than the previous row except 1^st row where number of spaces are N - 1. Hence we can say that there are total (N - rowNumber) spaces in the starting of each row.
Number of stars in each row is two more than the previous row except 1^st row where number of stars are 1. Hence we can say that there are total ((rowNumber - 1) * 2 + 1) stars between these spaces.

For N = 4,

Row	Spaces	Stars	Spaces
1	3	1	3
2	2	3	2
3	1	5	1
4	0	7	0

PseudoCode¶

function pattern(int N) {
    for (int i = 1; i <= N; i++) {
        for (int j = 1; j <= N - i; j++) {
            system.out.print(' ');
        }
        for (int j = 1; j <= (i - 1) * 2 + 1; j++) {
            system.out.print(' * ');
        }
        for (int j = 1; j <= N - i + 1; j++) {
            system.out.print(' ');
        }
        system.out.println();
    }
}

Refresher : Patterns¶

Question 1¶

TestCase¶

Input¶

Output¶

PseudoCode¶

Question 2¶

TestCase¶

Input¶

Output¶

PseudoCode¶

Question 3¶

TestCase¶

Input¶

Output¶

PseudoCode¶

Question 4¶

TestCase¶

Input¶

Output¶

Observation¶

PseudoCode¶

Question 5¶

TestCase¶

Input 1¶

Output 1¶

Input 2¶

Output 2¶

Observation¶

PseudoCode¶

Question 6¶

TestCase¶

Input 1¶

Output 1¶

Input 2¶

Output 2¶

Observation¶

PseudoCode¶

Question 7¶

TestCase¶

Input 1¶

Output 1¶

Input 2¶

Output 2¶

Observation¶

PseudoCode¶

Question 8¶

TestCase¶

Input 1¶

Output 1¶

Input 2¶

Output 2¶

Observation¶

PseudoCode¶

Question 9¶

TestCase¶

Input 1¶

Output 1¶

Input 2¶

Output 2¶

Observation¶

PseudoCode¶

function pattern(int N) { for (int i = 1; i <= N; i++) { for (int j = 1; j <= N - i; j++) { system.out.print(' '); } for (int j = 1; j <= i; j++) { system.out.print(' * '); } system.out.println(); } } ¶

Question 10¶

TestCase¶

Input 1¶

Output 1¶

Observation¶

PseudoCode¶

Question 11¶

TestCase¶

Input 1¶

Output 1¶

Observation¶

PseudoCode¶

`function pattern(int N) { for (int i = 1; i <= N; i++) { for (int j = 1; j <= N - i; j++) { system.out.print(' '); } for (int j = 1; j <= i; j++) { system.out.print(' * '); } system.out.println(); } }`
¶