Facebook Interview Question SDE1s
Country: United States
public class PrintDiamondShape {
public static void main(String[] args) {
// TODO Auto-generated method stub
int num =9;
int l=1;
for (int i = 0; i <=num/2; i++) {
for (int j = i; j < num/2; j++) {
System.out.print(" ");
}
for (int k = 0; k <l; k++) {
System.out.print("*");
}
for (int j = i; j < num/2; j++) {
System.out.print(" ");
}
System.out.println();
l= l+2;
}
int x=0;
for (int i = 0; i <num/2; i++) {
for (int j = 0; j <= i; j++) {
System.out.print(" ");
}
for (int k = 0; k <num-2-x; k++) {
System.out.print("*");
}
x=x+2;
for (int j = 0; j <= i; j++) {
System.out.print(" ");
}
System.out.println();
}
}
}
#include <stdlib.h>
#include <stdio.h>
void printUp(int n, int max, int space) {
if (n >= max) return;
for (int i = 0; i < space - 1; ++i) {
printf(" ");
}
for (int i = 0; i < n; ++i) {
printf("*");
}
printf("\n");
printUp(n + 2, max, space - 1);
}
void printDown(int n, int space) {
if (n <= 0) return;
for (int i = 0; i < space; ++i) {
printf(" ");
}
for (int i = 0; i < n; ++i) {
printf("*");
}
printf("\n");
printDown(n - 2, space + 1);
}
void print(int n) {
printUp(1, n, (n / 2) + 1);
printDown(n, 0);
}
int main(int argc, char **argv) {
print(5);
return 0;
}
Objective-C...
- (void) printDiamond:(int)n
{
if (n <= 0 || (n % 2 != 1)) {
NSLog(@"Bad Input");
return;
}
[self printDiamondLine:n spaceCount:(n/2)];
}
- (void) printDiamondLine:(int)n spaceCount:(int)spaceCount
{
if (spaceCount == 0) {
NSLog(@"%@", [self getStringOfK:n ch:@"*"]);
}
else {
NSLog(@"%@%@", [self getStringOfK:spaceCount ch:@" "], [self getStringOfK:(n - 2 * spaceCount) ch:@"*"]);
[self printDiamondLine:n spaceCount:(spaceCount - 1)];
NSLog(@"%@%@", [self getStringOfK:spaceCount ch:@" "], [self getStringOfK:(n - 2 * spaceCount) ch:@"*"]);
}
}
- (NSString *) getStringOfK:(int)k ch:(NSString *)ch
{
NSString *output = @"";
for (int i = 0; i < k; i++) {
output = [output stringByAppendingString:ch];
}
return output;
}
#include <stdio.h>
int main()
{
int n, c, k, space = 1;
printf("Enter number of rows\n");
scanf("%d", &n);
space = n - 1;
for (k = 1; k <= n; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space--;
for (c = 1; c <= 2*k-1; c++)
printf("*");
printf("\n");
}
space = 1;
for (k = 1; k <= n - 1; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space++;
for (c = 1 ; c <= 2*(n-k)-1; c++)
printf("*");
printf("\n");
}
return 0;
}
#include <stdio.h>
int main()
{
int n, c, k, space = 1;
printf("Enter number of rows\n");
scanf("%d", &n);
space = n - 1;
for (k = 1; k <= n; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space--;
for (c = 1; c <= 2*k-1; c++)
printf("*");
printf("\n");
}
space = 1;
for (k = 1; k <= n - 1; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space++;
for (c = 1 ; c <= 2*(n-k)-1; c++)
printf("*");
printf("\n");
}
return 0;
}
//O(n) time
public void print(int n){
if(n <= 0 || n % 2 != 0){
throw new IllegalArgumentException();
}
for(int i = 1; i < n; i += 2){
printStars(i);
System.out.print('\n');
}
printStars(n);
for(int i = n - 2; i >= 1; i -= 2){
System.out.print('\n');
printStars(i);
}
}
private void printStars(int n){
while(n > 0){
System.out.print('*');
n--;
}
}
using System;
// To execute C#, please define "static void Main" on a class
// named Solution.
class Solution
{
static void PrintDiamond(int n)
{
int count = n/2;
for(int i=0;i<n*2;i++)
{
if(i%2!=0)
Console.WriteLine("{0}{1}",new String(' ',i<n ? count-- :count++),new String('*', i<n ? i :n*2 - i ));
}
}
static void Main(string[] args)
{
PrintDiamond(399);
}
}
public static void PrintStarPattern(int N)
{
PrintPatternInternal(1, N, 2);
PrintPatternInternal(N-2, N, -2);
}
private static void PrintPatternInternal(int k, int N, int delta)
{
if (k < 1 || k > N)
{
return;
}
PrintLine(k, N);
PrintPatternInternal(k + delta, N, delta);
}
private static void Print(int n, char c)
{
if (n < 0)
{
throw new ArgumentException();
}
for (int i = 1; i <= n; i++)
{
Console.Write(c);
}
}
private static void PrintLine(int k, int N)
{
Print((N - k)/2, ' ');
Print(k, '*');
Console.WriteLine();
}
public static void PrintStarPattern(int N)
{
PrintPatternInternal(1, N, 2);
PrintPatternInternal(N-2, N, -2);
}
private static void PrintPatternInternal(int k, int N, int delta)
{
if (k < 1 || k > N)
{
return;
}
PrintLine(k, N);
PrintPatternInternal(k + delta, N, delta);
}
private static void Print(int n, char c)
{
if (n < 0)
{
throw new ArgumentException();
}
for (int i = 1; i <= n; i++)
{
Console.Write(c);
}
}
private static void PrintLine(int k, int N)
{
Print((N - k)/2, ' ');
Print(k, '*');
Console.WriteLine();
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace DiamondPatternOfStars
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter numer:");
int num = Convert.ToInt32(Console.ReadLine());
if(num % 2 == 0)
{
Console.WriteLine("Enter ODD number.");
return;
}
PrintStar(num / 2, 1, num-1, num);
}
static void PrintStar(int Pos, int TotalStars, int LeftRows, int TotalRows)
{
if (LeftRows < 0)
{
return;
}
for (int i = 0; i < TotalStars + Pos; i++)
{
if(i < Pos)
{
Console.Write(" ");
}
else
{
Console.Write("*");
}
}
Console.WriteLine();
if (LeftRows > TotalRows / 2)
{
PrintStar(Pos - 1, TotalStars + 2, LeftRows - 1, TotalRows);
}
else
{
PrintStar(Pos + 1, TotalStars - 2, LeftRows - 1, TotalRows);
}
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace DiamondPatternOfStars
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter numer:");
int num = Convert.ToInt32(Console.ReadLine());
if(num % 2 == 0)
{
Console.WriteLine("Enter ODD number.");
return;
}
PrintStar(num / 2, 1, num, num);
}
static void PrintStar(int Pos, int TotalStars, int LeftRows, int TotalRows)
{
if (LeftRows < -1)
{
return;
}
for (int i = 0; i < TotalStars + Pos; i++)
{
if(i < Pos)
{
Console.Write(" ");
}
else
{
Console.Write("*");
}
}
Console.WriteLine();
if (LeftRows > TotalRows / 2)
{
PrintStar(Pos - 1, TotalStars + 2, LeftRows - 1, TotalRows);
}
else
{
PrintStar(Pos + 1, TotalStars - 2, LeftRows - 1, TotalRows);
}
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace DiamondPatternOfStars
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter numer:");
int num = Convert.ToInt32(Console.ReadLine());
if(num % 2 == 0)
{
Console.WriteLine("Enter ODD number.");
return;
}
PrintStar(num / 2, 1, num, num);
}
static void PrintStar(int Pos, int TotalStars, int LeftRows, int TotalRows)
{
if (LeftRows < -1)
{
return;
}
for (int i = 0; i < TotalStars + Pos; i++)
{
if(i < Pos)
{
Console.Write(" ");
}
else
{
Console.Write("*");
}
}
Console.WriteLine();
if (LeftRows > TotalRows / 2)
{
PrintStar(Pos - 1, TotalStars + 2, LeftRows - 1, TotalRows);
}
else
{
PrintStar(Pos + 1, TotalStars - 2, LeftRows - 1, TotalRows);
}
}
}
}
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace DiamondPatternOfStars
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Enter numer:");
int num = Convert.ToInt32(Console.ReadLine());
if(num % 2 == 0)
{
Console.WriteLine("Enter ODD number.");
return;
}
PrintStar(num / 2, 1, num, num);
}
static void PrintStar(int Pos, int TotalStars, int LeftRows, int TotalRows)
{
if (LeftRows < -1)
{
return;
}
for (int i = 0; i < TotalStars + Pos; i++)
{
if(i < Pos)
{
Console.Write(" ");
}
else
{
Console.Write("*");
}
}
Console.WriteLine();
if (LeftRows > TotalRows / 2)
{
PrintStar(Pos - 1, TotalStars + 2, LeftRows - 1, TotalRows);
}
else
{
PrintStar(Pos + 1, TotalStars - 2, LeftRows - 1, TotalRows);
}
}
}
}
void print(int n) {
using std::cout;
// cout << "n = " << n << " Diamond shape is as follows:" << endl;
int width = 0; // distance from center, also we always print middle *
int half = n/2; // floored
for(int i = 0; i < n; ++i){
if(i <= half) {
width++;
} else {
width--;
}
for(int j = 0; j < n; ++j){
if(j > half - width && j < half + width){
cout << '*';
} else {
cout << ' ';
}
}
cout << endl;
}
}
Javascript:
function printRow(n, dir){
n = dir? n += 2 : n -= 2;
dir = n == total? dir = false : dir;
var rowS = "";
var spacesN = (total - n) / 2;
for(var i = 1; i <= total; i++){
var c = i <= spacesN || i > spacesN + n ? " ": "*";
rowS += c;
}
console.log(rowS);
if(n > 0){
printRow(n, dir);
}
}
var dir = true;
var total = 151;
var x = -1;
printRow(x, dir);
function printRow(n, dir){
n = dir? n += 2 : n -= 2;
dir = n == total? dir = false : dir;
var rowS = "";
var spacesN = (total - n) / 2;
for(var i = 1; i <= total; i++){
var c = i <= spacesN || i > spacesN + n ? " ": "*";
rowS += c;
}
console.log(rowS);
if(n > 0){
printRow(n, dir);
}
}
var dir = true;
var total = 151;
var x = -1;
printRow(x, dir);
Simple recursive solution using Python.
Idea: Keep incrementing the number of stars in delta of '2' until it reaches the value of 'n' after which start decrementing the delta
def star_print(n, k=1, delta=2):
if k < 0:
return
t = (n - k) / 2
print ' ' * t + '*' * k + ' ' * t
if k == n:
delta = -delta
star_print(n, (k+delta), delta)
#given odd number. Print diamond
#o(n) iterative
def printDiamond(n):
spc=int(n-1)/2
for i in range(1,n+2,2):
print spc*' '+ i*'*'
spc=spc-1
spc=1
for j in range(n,0,-2):
if j==n:
continue
print spc*' '+ j*'*'
spc=spc+1
printDiamond(5)
print "Next item"
#printDiamond(7)
def printDiagmonRecUtil(n,spc,spcPrev,i):
#if n == 5:
# printDiagmonRecUtil(n,1)
if i!=n and spcPrev>=spc:
print spc * ' ' + i * '*'
printDiagmonRecUtil(n, spc - 1, spcPrev, i + 2)
elif i<0 or n<0:
return
elif i==n:
print spc*' '+ n*'*'
spcPrev=spc
spc=spc+1
n=n-2
i=n
printDiagmonRecUtil(n, spc, spcPrev, i)
def printDiamondRec(n):
spc=int(n-1)/2
printDiagmonRecUtil(n,spc,spc,1)
printDiamondRec(5)
printDiamondRec(7)
Yet another solution in python!!
from itertools import chain
from __future__ import print_function
def print_diamond(n):
number_of_stars = list(chain(xrange(1, n+1, 2),
xrange(n-2, 0, -2)))
stars = []
for e in number_of_stars:
half = (n - e) / 2
stars.append(' ' * half + '*' * e + ' ' * half)
map(lambda x: print(x), stars)
In Scala
object DiamondOddNumber {
def main(args: Array[String]): Unit = {
printDiamondPattern(7)
}
def printDiamondPattern(num:Int) = {
def f(n:Int) = {
val whitespace = (num - n) / 2
1.to(whitespace).foreach(elem => print(' '))
1.to(n).foreach(elem =>
if (elem % 2 == 1) print('o')
else print('*')
)
1.to(whitespace).foreach(elem => print(' '))
println
}
1.to(num).filter(n => n % 2 != 0).foreach(n => f(n))
(num-1).to(1).by(-1).filter(n => n % 2 != 0).foreach(n => f(n))
}
}
c# implementation using recursion
public static void PrintDiamond(int n)
{
if (n <= 0 || n % 2 == 0)
return;
PrintDiamond(5, 1);
}
private static void PrintDiamond(int n, int curr)
{
Console.WriteLine(s);
if (curr == n)
return;
PrintDiamond(n, curr + 2);
Console.WriteLine(s);
}
private static string GeneratePattern(int n, int curr)
{
var sb = new StringBuilder();
int diff = (n - curr) / 2;
for (int i=0; i < diff; i++)
sb.Append(' ');
for (int i=0; i < curr; i++)
sb.Append('*');
for (int i=0; i < diff; i++)
sb.Append(' ');
return sb.ToString();
}
public class PrintDiamondShape {
public static void main(String[] args) {
// TODO Auto-generated method stub
int num =9;
int l=1;
for (int i = 0; i <=num/2; i++) {
for (int j = i; j < num/2; j++) {
System.out.print(" ");
}
for (int k = 0; k <l; k++) {
System.out.print("*");
}
for (int j = i; j < num/2; j++) {
System.out.print(" ");
}
System.out.println();
l= l+2;
}
int x=0;
for (int i = 0; i <num/2; i++) {
for (int j = 0; j <= i; j++) {
System.out.print(" ");
}
for (int k = 0; k <num-2-x; k++) {
System.out.print("*");
}
x=x+2;
for (int j = 0; j <= i; j++) {
System.out.print(" ");
}
System.out.println();
}
}
}
My recursive solution :
def line(n,l):
arr = [" "] * l
tmp = "".join(arr)
for i in xrange(n):
tmp = tmp + "*"
return tmp
def recprint(n,m,b,l=0):
if n > 0:
recprint(n-2,0,b,l+1)
print line(n,l)
if m == 0: return
if m != 0:
if n==b: l = (n-1)/2
if m >= b: return
recprint(0,m+2,b,l-1)
print line(m,l)
recprint(11,1,11)
public static void print(int num) {
int upCounter = 1;
int downCounter = num;
print(num, upCounter, downCounter);
}
private static void print(int num, int upCounter, int downCounter) {
if(upCounter > num)
return;
print(num, upCounter+1, downCounter-1);
int spaces = Math.abs(upCounter - downCounter);
for(int i = 0; i < spaces/2; i++)
System.out.print(" ");
int stars = num - spaces;
for(int i = 0; i < stars; i ++)
System.out.print("*");
System.out.println();
}
public static void print(int num) {
int upCounter = 1;
int downCounter = num;
print(num, upCounter, downCounter);
}
private static void print(int num, int upCounter, int downCounter) {
if(upCounter > num)
return;
print(num, upCounter+1, downCounter-1);
int spaces = Math.abs(upCounter - downCounter);
for(int i = 0; i < spaces/2; i++)
System.out.print(" ");
int stars = num - spaces;
for(int i = 0; i < stars; i ++)
System.out.print("*");
System.out.println();
}
public static void print(int num) {
int upCounter = 1;
int downCounter = num;
print(num, upCounter, downCounter);
}
private static void print(int num, int upCounter, int downCounter) {
if(upCounter > num)
return;
print(num, upCounter+1, downCounter-1);
int spaces = Math.abs(upCounter - downCounter);
for(int i = 0; i < spaces/2; i++)
System.out.print(" ");
int stars = num - spaces;
for(int i = 0; i < stars; i ++)
System.out.print("*");
System.out.println();
}
public class diamondShapeStars {
public static void printStar(int n, int diff, int i){
if(i == n) diff = -diff;
if(i<1) return;
int space = (n-i)/2;
for(int x = 0 ; x < space; x++) System.out.print(" ");
for(int x = 0 ; x < i; x++) System.out.print("*");
for(int x = 0 ; x < space; x++) System.out.print(" ");
System.out.println("");
printStar(n, diff, i+diff);
}
public static void main(String args[]){
printStar(5, 2, 1);
}
}
public class diamondShapeStars {
public static void printStar(int n, int diff, int i){
if(i == n) diff = -diff;
if(i<1) return;
int space = (n-i)/2;
for(int x = 0 ; x < space; x++) System.out.print(" ");
for(int x = 0 ; x < i; x++) System.out.print("*");
for(int x = 0 ; x < space; x++) System.out.print(" ");
System.out.println("");
printStar(n, diff, i+diff);
}
public static void main(String args[]){
printStar(5, 2, 1);
}
}
#include<iostream>
using namespace std;
int main()
{
int size=8;
int i=0;
for (i=1;i<size;i++) {
for (int j=size;j>i;j--) {
cout<<" ";
}
for (int k=0;k<i;k++) {
cout<<" *";
}
cout<<endl;
}
for (i=size;i>0;i--) {
for (int j=size;j>i;j--) {
cout<<" ";
}
for (int k=0;k<i;k++) {
cout<<" *";
}
cout<<endl;
}
return 0;
}
#include <stdio.h>
int main()
{
int n, c, k, space = 1;
printf("Enter number of rows\n");
scanf("%d", &n);
int s = n/2;
n = n-s;
space = n - 1;
for (k = 1; k <= n; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space--;
for (c = 1; c <= 2*k-1; c++)
printf("*");
printf("\n");
}
space = 1;
for (k = 1; k <= n - 1; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space++;
for (c = 1 ; c <= 2*(n-k)-1; c++)
printf("*");
printf("\n");
}
return 0;
}
#include <stdio.h>
int main()
{
int n, c, k, space = 1;
printf("Enter number of rows\n");
scanf("%d", &n);
int s = n/2;
n = n-s;
space = n - 1;
for (k = 1; k <= n; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space--;
for (c = 1; c <= 2*k-1; c++)
printf("*");
printf("\n");
}
space = 1;
for (k = 1; k <= n - 1; k++)
{
for (c = 1; c <= space; c++)
printf(" ");
space++;
for (c = 1 ; c <= 2*(n-k)-1; c++)
printf("*");
printf("\n");
}
return 0;
}
- Hien Luong May 20, 2017function drawDiamond(n) { var reduce = 2; var star = 1, space = (n - 1)/2; for (var i = 0; i < n; i++) { console.log(loopStr(space," ") + loopStr(star,"*") + loopStr(space," ")); star = star + reduce; space = ((n - star)/2); if (star == n) reduce = -2; } } function loopStr(n,str) { var result = ""; for (var i = 0; i < n; i++) { result += str; } return result; } console.log(drawDiamond(7))