Sam is curious about symmetric patterns, so he decided to create one.
For every value of ‘N’, return the symmetry as shown in the example.
Example:
Input: ‘N’ = 3
Output:
* *
* * * *
* * * * * *
* * * *
* *
The first and only line contains an integer, ‘N’.
Print the pattern as specified.
1 <= N <= 25
Time Limit: 1 sec
3
* *
* * * *
* * * * * *
* * * *
* *
1
*
Iterate to all the cells.
Approach:
The solution to the problem lies in just iterating to all the (2*N-1)*(2*N) cells of the pattern and printing every cell.
The steps are as follows :
Function void symmetry(int ‘N’)
O(N * N)
There are two nested loops, so time complexity would be the order of N * N.
Hence the time complexity is O(N * N).
O(1).
No extra space is used as we are just printing the pattern.
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Interview problems
c++ code
void print1(int n){
int k=2*n+2;
for(int i=0;i<n;i++){
for(int j=0;j<=i;j++){
cout<<"*"<<" ";
}
for(int j=0;j<k;j++){
cout<<" ";
}
for(int j=0;j<=i;j++){
cout<<"*"<<" ";
}
k-=4;
cout<<endl;
}
}
void print2(int n){
int k=4;
for(int i=1;i<n;i++){
for(int j=0;j<n-i;j++){
cout<<"*"<<" ";
}
for(int j=0;j<k;j++){
cout<<" ";
}
for(int j=0;j<n-i;j++){
cout<<"*"<<" ";
}
k+=4;
cout<<endl;
}
}
void symmetry(int n) {
// Write your code here.
print1( n);
print2( n);
}
Interview problems
Butterfly pattern
public class Solution {
public static void symmetry(int n) {
// 1st half
for(int i=1;i<=n;i++){
for(int j=1;j<=i;j++){
System.out.print("*"+" ");
}
//space-->2*(n-i)
for(int j=1;j<=2*(n-i);j++){
System.out.print(" ");
}
//Stars
for(int j=1;j<=i;j++){
System.out.print("*"+" ");
}
System.out.println();
}
// 2nd half
for(int i=n-1;i>=1;i--){
for(int j=1;j<=i;j++){
System.out.print("*"+" ");
}
//space-->2*(n-i)
for(int j=1;j<=2*(n-i);j++){
System.out.print(" ");
}
//Stars
for(int j=1;j<=i;j++){
System.out.print("*"+" ");
}
System.out.println();
}
}
}
Interview problems
c++ code
void symmetry(int n) {
for(int i=1;i<=n;i++){
for(int j=0;j<i;j++){
cout<<"* ";
}
for(int j=0;j<2*(n-i);j++){
cout<<" ";
}
for(int j=0;j<i;j++){
cout<<"* ";
}
cout<<endl;
}
for(int i=1;i<=n;i++){
for(int j=0;j<n-i;j++){
cout<<"* ";
}
for(int j=0;j<2*i;j++){
cout<<" ";
}
for(int j=0;j<n-i;j++){
cout<<"* ";
}
cout<<endl;
}
}Interview problems
Symmetry Easy || 2 Loops || Pattern
def symmetry(n: int):
for i in range(1,n+1):
print("* "*(i),end="")
print(" "*4*(n-i),end="")
print("* "*(i),end="")
print()
for i in range(n-1,0,-1):
print("* "*(i),end="")
print(" "*4*(n-i),end="")
print("* "*(i),end="")
print()
pass
Interview problems
solution
void symmetry(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;j--){
cout<<" " ;
}
for(int j=n;j>2*i;j--){
cout<<" " ;
}
for(int j=0;j<i;j++){
cout<<"* ";
}
cout<<endl;
}
for(int i=0;i<n;i++){
for(int j=n;j>i;j--){
cout<<"* ";
}
for(int j=0;j<2*i;j++){
cout<<" " ;
}
for(int j=0;j<2*i;j++){
cout<<" " ;
}
for(int j=n;j>i;j--){
cout<<"* ";
}
cout<<endl;
}
}
Interview problems
C++ solution(beats 100%)
void symmetry(int n) {
// Write your code here.
for(int i=0;i<n;i++)
{
for(int j=0;j<i+1;j++)
{
cout<<"* ";
}
for(int j=0;j<n-i*2+1;j++)
{
cout<<" ";
}
for(int j=0;j<i+1;j++)
{
cout<<"* ";
}
cout<<"\n";
}
for(int i=0;i<n-1;i++)
{
for(int j=0;j<n-1-i;j++)
{
cout<<"* ";
}
for(int j=0;j<n-1+2*1;j++)
{
cout<<" ";
}
for(int j=0;j<n-1-i;j++)
{
cout<<"* ";
}
cout<<"\n";
}
}
Interview problems
Easy JAVA solution
for(int row=0; row<n; row++){
for(int star=0; star<row+1; star++){
System.out.print("* ");
}
for(int space=1; space<=2*(n-1-row); space++){
System.out.print(" ");
}
for(int star=0; star<row+1; star++){
System.out.print("* ");
}
System.out.println();
}
for(int row=0; row<n-1; row++){
for(int star=0; star<n-1-row; star++){
System.out.print("* ");
}
for(int space=1; space<=2*(1+row); space++){
System.out.print(" ");
}
for(int star=0; star<n-1-row; star++){
System.out.print("* ");
}
System.out.println();
}
}Interview problems
C++ Solution
void symmetry(int n) {
// Write your code here.
for (int i = 0; i < n; i++) {
// Left stars
for (int j = 0; j <= i; j++) {
cout << "* ";
}
// Spaces
for (int j = 0; j < 2 * (n - i - 1); j++) {
cout << " ";
}
// Right stars
for (int j = 0; j <= i; j++) {
cout << "* ";
}
cout << endl;
}
// Lower half of the pattern
for (int i = n - 2; i >= 0; i--) {
// Left stars
for (int j = 0; j <= i; j++) {
cout << "* ";
}
// Spaces
for (int j = 0; j < 2 * (n - i - 1); j++) {
cout << " ";
}
// Right stars
for (int j = 0; j <= i; j++) {
cout << "* ";
}
cout << endl;
}
}
Interview problems
Butterfly Pattern solved using functions in cpp
void lowerPattern(int &n,int &i){
for(int j=n;j>=i;j--){
cout<<"* ";
}
}
void upperPattern(int &n,int &i){
for(int j=1;j<=i;j++){
cout<<"* ";
}
}
void symmetry(int n) {
// Write your code here.
for(int i=1;i<=n;i++){
upperPattern(n,i);
for(int k=2*n;k>2*i;k--){
cout<<" ";
}
upperPattern(n,i);
cout<<endl;
}
for(int i=2;i<=n;i++){
lowerPattern(n,i);
for(int k=2;k<2*i;k++){
cout<<" ";
}
lowerPattern(n,i);
cout<<endl;
}
}
Interview problems
Symmetry
void symmetry(int n) {
int space = 2*n-2;
for(int i = 1; i<=2*n-1; i++){
int star = i;
if(i>n) star = 2*n-i;
for(int j = 1; j<=star; j++){
cout<<"*"<<" ";
}
for(int j = 1; j<=space; j++){
cout<<" ";
}
for(int j=1; j<=star; j++){
cout<<"*"<<" ";
}
cout<<endl;
if(i<n) space = space - 2;
else space = space + 2;
}
}
