Last Updated: 26 Nov, 2020
Pattern: Triangle of numbers
Easy
Asked in companies
Ninja is given a pattern. Now he is asked to print the same pattern for any given ‘N’ number of rows.
For example, Pattern for ‘N’ = 4 will be.
1
232
34545
4567654
Input Format:
The first line contains an integer 'T' which denotes the number of test cases or queries to be run.
The first line of each test case contains a single integer ‘N’ denoting the number of rows for which pattern needs to be printed.
Output Format:
The output of each test case will be 'N' strings denoting the pattern printed for the given ‘N’ number of rows.
Output of each test case will be printed on a separate line.
Constraints:
1 <=T <= 5
1 <= N <= 100
Where ‘T’ is the total number of test cases and ‘N’ is the given number of rows for which pattern needs to be printed.
Time limit: 1 sec
Approaches
We can observe that there is an ‘N’ number of rows where ‘N’ is the total number of rows to be printed. And each row exactly contains ‘N’ - ‘row’ number of spaces where ‘row’ denotes the row number starting from topmost as 1. Also, when we go left to right the value of each element in a particular row increases by one starting from the ‘row’ number and then decrements in the same column from 2* ‘row’ - 1 till 'row'.
Algorithm:
- Declare an array of strings say ‘result’ for storing the pattern.
- Declare a variable ‘row’ for keeping track of the number of rows
- Run an outer loop from ‘row’ = ‘1 to ‘row’ = ‘N’.
- Declare an empty string for storing the values in the current row.
- Run an inner loop for printing spaces from ‘space’ = 1 to ‘space’ = ‘N’ - ‘row’ (where ‘row’ is the current row number).
- Initialize a variable say ‘val’ = ‘row’.
- Run an inner loop from ‘currCol’ = 1 to ‘currCol’ = ‘row' to printing values in increasing order.
- Append ‘val’ to the current string. and increment ‘val’ by 1.
- Set ‘val’ = 2 * (‘row’ - 1)
- Run an inner loop from ‘currCol’ = ‘val’ to ‘currCol’ = ‘row' to print values in decreasing order.
- Append ‘currCol’ to the current string.
- Add current string into ‘result’.
- Return ‘result’.