Ninja was very fond of patterns. For a given integer ‘N’, he wants to make the Reverse N-Star Triangle.
Example:
Input: ‘N’ = 3
Output:
*****
***
*
The first and only line of each test case contains an integer ‘N’.
Print the output as specified.
1 <= N <= 20
Time Limit: 1 sec
3
*****
***
*
The first row contains five stars.
The second row contains one space, followed by three stars.
The third row contains two spaces, followed by a star.
1
*
Iterate to all the cells.
Approach:
The solution is iterating on the pattern and print every cell using ‘*’ or spaces.
The steps are as follows :
Function void nStar(int ‘N’)
O( N* N ), Where N is the given input integer.
Two nested loops are running N*(2*N-1) times so that time complexity would be the order of N*N.
Hence the time complexity is O( N * N ).
O(1)
Since we are using constant extra space.
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Interview problems
cpp solution
void nStarTriangle(int n) {
// Write your code here.
for (int i=0;i<n;i++)
{
for (int j = 0; j < i; j++) {
cout << " ";
}
for (int j = 0; j < 2*n-(2 * i + 1);j++)
{
cout<<"*";
}
for (int j=0;j<i;j++)
{
cout<<" ";
}
cout<<endl;
}
}
Interview problems
solution
void nStarTriangle(int n) {
// Write your code here.
for(int i=0;i<n;i++){
for(int j=0;j<i;j++){
cout<<" ";
}
for(int j=n;j>(2*i-n+1);j--){
cout<<"*";
}
for (int j = 0; j < i; j++) {
cout << " ";
}
cout<<endl;
}
}
Interview problems
c++
void nStarTriangle(int n) {
for(int i=0;i<n;i++){
for(int j=0;j<=i-1;j++){
cout<<" ";
}
for(int j=0;j<2*(n-i)-1;j++){
cout<<"*";
}
cout<<endl;
}
}Interview problems
Pattern
void nStarTriangle(int n) {
// Write your code here.
for(int i=0;i<n;i++){
//space
for(int j=0;j<i;j++){
cout<<" ";
}
for(int j=0;j<2*n-(2*i+1);j++){
cout<<"*";
}
for(int j=0;j<i;j++){
cout<<" ";
}
cout<<endl;
}
}
Interview problems
solved in cpp
void nStarTriangle(int n) {
// Write your code here.
for(int i =0; i<n; i++){
//space
for(int j=0; j<i; j++){
cout<<" ";
}
//star
for(int j=0; j<(2*n-2*i-1); j++){
cout<<"*";
}
//space
for(int j=0; j<i; j++){
cout<<" ";
}
cout<<endl;
}
}
Interview problems
Reverse N-Star Triangle
void nStarTriangle(int n) {
// Write your code here.
for(int i=0; i<n; i++){
for(int j=0; j<i; j++){
cout<< " ";
}
for(int k=0; k<2*n-(2*i +1); k++){
cout<< "*";
}
cout<< endl;
}
}
Interview problems
Beginner Friendly Solution || C++
void nStarTriangle(int n) {
// Write your code here.
for(int i = n;i>=1;i--){
for(int j =0;j<n-i;j++){
cout<<" ";
}
for(int k = 0;k<(2*i)-1;k++){
cout<<"*";
}
cout<<endl;
}
}
Interview problems
Reverse Star Triangle Solution in Java
public class Solution {
public static void nStarTriangle(int n) {
// Write your code here
for(int i=n; i>=1; i--){
// for spaces
for(int j=(n-i); j>0; j--){
System.out.print(" ");
}
// for stars
for(int k=1; k<=(2*i-1); k++){
System.out.print("*");
}
System.out.println();
}
}
}Interview problems
Python code with only one loop.
def nStarTriangle(n: int) -> None:
i = n
spaces = 0
while i >= 0:
print(spaces * ' ' + (2*i - 1) * '*' + spaces * ' ', end='')
print()
spaces += 1
i -= 1This is just the opposite of the last problem, where you need to print the opposite pattern.
Interview problems
Java code with 3 loops
public class Solution {
public static void nStarTriangle(int n) {
// Write your code here
for(int i=1;i<=n;i++){//loop for rows
for(int j=1;j<=i-1;j++){ //loop for spaces
System.out.print(" ");
}
for(int k=1;k<=2*n-((2*i)-1);k++){ //loop for *
System.out.print("*");
}
System.out.println();
}
}
}
