CareerCup

Common Question on Combination.

Write recursive function which will limit the maximum call upto depth 3 and manipulate the string content.

str is the string combination, k is start from 0, n is the string length
void findComp(char* str, int k, int n){
if(k == n-1){
str[k] = 'p';
str[n] = '\0';
printf("str=%s\n", str);
str[k] = 'o';
str[n] = '\0';
printf("str=%s\n", str);
}else{
str[k] = 'p';
findComp(str, k+1, n);
str[k] = 'o';
findComp(str, k+1, n);
}
}

public class Main {
public static void main(String[] args) {
combinations("hello", "", 3);
}

private static void combinations(String sourceString, String accum,
int limit) {
if (sourceString == null || sourceString.length() == 0
|| "".equals(sourceString) || limit == 0) {
System.out.println(accum);
} else {
for (char ch : sourceString.toCharArray()) {
combinations(sourceString, accum + ch, limit - 1);
}
}
}
}

public void printString(List chars, int reqLength, int currentLength, StringBuilder stbd){

if(reqLength == currentLength)
{
	System.out.println(stbd);
	return;
}

	Iterator itr = chars.iterator();
	 while(itr.hasNext()){
		stbd.append(((Character)itr.next()).charValue());
		printString(chars, reqLength, currentLength+1, stbd);
		stbd.delete(stbd.length()-1);
	}
}

void permute_chars(std::string letters, int length, std::string permutaion="")
{
	if( length == 0 )
	{
		std::cout<<permutaion<<std::endl;
		return;
	}

	for(size_t i=0; i<letters.size(); i++)
		permute_chars(letters, length-1, permutaion+letters.at(i));
	
}

This can be done without recursion...

if number of letters is <=10, n<=10

char a[n],int len,int b[len]={0,0...0}
int p=n^len,i=0,cntr=0,j,iterate;
for i=0 to p-1
j=i
while j>0
b[cntr]=j%n
cntr++
j/=n
cntr=0
for iterate=0 to len
print a[b[iterate]]
print newline

my bad lost indentation
if number of letters is <=10, n<=10

char a[n],int len,int b[len]={0,0...0}
int p=n^len,i=0,cntr=0,j,iterate;
for i=0 to p-1
 j=i
 while j>0
  b[cntr]=j%n
  cntr++
  j/=n
 cntr=0
 for iterate=0 to len
  print a[b[iterate]]
 print newline

<pre lang="" line="1" title="CodeMonkey35868" class="run-this">private static void GetAllPermutations(char[] tokens, int len, ref HashSet<string> words)
{
if (len == 0)
{
return;
}

words = new HashSet<string>();
for (int i = 0; i < tokens.Length; i++)
{
words.Add("" + tokens[i].ToString());
}

HashSet<string> lastSet = words;

for(int size = 2; size <= len; size++)
{
HashSet<string> currentSet = new HashSet<string>();
foreach (var word in lastSet)
{
for (int i = 0; i < tokens.Length; i++)
{
char currentChar = tokens[i];
for (int k = 0; k <= word.Length; k++)
{
currentSet.Add(word.Insert(k, currentChar.ToString()));
}
}
}

lastSet = currentSet;
words = currentSet;
}
}</pre><pre title="CodeMonkey35868" input="yes">
</pre>

// 'letters' is an array of letters
List<string> GetWords(char[] letters, int length)
{
List<string> currentSet = new List<string>();
List<string> nextSet = new List<string>();
List<string> tempSet;

for (int l = 0; l < letterCount; l++)
{
currentSet.Add(string.Empty);
}

for (int x = 0; x < length; x++)
{
foreach(string item in currentSet)
{
for (int l = 0; l < letterCount; l++)
{
nextSet.Add(item + letters[l]);
}
}

currentSet.Clear();
tempSet = currentSet;
currentSet = nextSet;
nextSet = tempSet;
}

return currentSet;
}

void fun(char str[],int n,char cur[],int index)
{
  if(index==n)
  {
    cur[index]='\0';
    printf("\n%s",cur);
    return;
  }
  for(int i=0;i<strlen(str);i++)
  {
   cur[index]=str[i];
   fun(str,n,cur,index+1);

  }
}

#include <stdio.h>
#include <math.h>
#define LENGTH 3
#define CHARACTERS 2
void convert_to_binary(int a[],int i) {

int j = LENGTH - 1;

for (j = LENGTH - 1; j >= 0; --j) {
a[j] = i%2;
i = i/2;
if (i == 0) break;
}
}
int main() {
int last_no = (int)(pow(CHARACTERS,LENGTH)) - 1;
int i = 0, j = 0;
int a[LENGTH] = {0,};
char p[CHARACTERS] = "po";

for (i = 0; i <= last_no; ++i) {
convert_to_binary(a,i);
for (j = 0; j < LENGTH; ++j)
printf("%c",p[a[j]]);
printf(" ");
memset(a,0,sizeof(a));
}
printf("\b\n");
getchar();
}

#include <string>
#include <iostream>

using namespace std;

void allp(const string& s, int lth, string& out)
{
if (out.size() == lth)
{
cout << out << endl;
return;
}

for (int i = 0; i < s.size(); ++i)
{
out.append(1, s.at(i));
allp(s, lth, out);
out = out.substr(0, out.size() - 1);
}
}
int main()
{
string out;
allp("op", 3, out);
}