words from letters - ios

Question

I am working in iOS, and I am facing one problem. I have 6 letters, and I want to find all strings that can be generated by these 6 letters. The sequence and length of the string doesn't matter here, also the meaning of the string doesn't matter because we can check the string with a dictionary to find if it is a valid word or not.
So is there any algorithm to find this?
For example:
Input 6 letters are : N T L P A E
Expected output will be:
plan
net
planet
lan
tea
lap
..
..
Here the words in the output are only the valid words, but the output should contain all possible words, even invalid words.

Answer 1

This should probably solve this:
+ (void) logPermutations:(NSArray*)objects
{
if (objects == nil || [objects count] == 0) {
return;
}
NSMutableArray* copy = [objects mutableCopy];
[self logPermutations:copy logedSoFar:#""];
}
+ (void) logPermutations:(NSMutableArray*)objects
logedSoFar:(NSString*)log
{
if (objects == nil || [objects count] == 0) {
return;
}
NSUInteger count = [objects count];
for (NSUInteger i = 0; i < count; ++i) {
id removed = [objects objectAtIndex:i];
[objects removeObjectAtIndex:i];
NSString* newlog = [NSString stringWithFormat:#"%#%#",log,[removed description]];
NSLog(#"%#",newlog);
[self logPermutations:objects logedSoFar:newlog];
[objects insertObject:removed atIndex:i];
}
}

Answer 2

-(NSMutableArray*)genValidWords:(NSString*)tiles
{
/*===============EMPTY PREVIOUS ARRAY=================*/
FINAL_VALID_WORDS=[[NSMutableArray alloc] init];
posWords=[[NSMutableArray alloc] init];
genWords=[[NSArray alloc] init];
/*============EMPTY PREVIOUS ARRAY FINISH=============*/
/*===============POSSIABLE NO OF WORDS FROM GIVEN LETTERS=================*/
int length=[tiles length];
int total=0;
for(long i=2;i<[tiles length]+1;i++)
total=total+([self factorialX:length]/[self factorialX:length-i]);
NSLog(#"POSSIABLE NO OF WORDS FROM LETTERS \"%#\" IS %d",tiles,total);
/*===============POSSIABLE NO OF WORDS FROM GIVEN LETTERS FINISH=================*/
/*===============GET ARRAY OF ALL POSSIABLE WORDS FROM GIVEN LETTERS=============*/
for(int i=2;i<[tiles length]+1;i++)
{
genWords=getPermutations(tiles, i);
[posWords addObjectsFromArray:genWords];
}
NSLog(#"%#",posWords);
return posWords;
}
static NSMutableArray *results;
void doPermute(NSMutableArray *input, NSMutableArray *output, NSMutableArray *used, int size, int level)
{
if (size == level)
{
NSString *word = [output componentsJoinedByString:#""];
//if(check(word))
[results addObject:word];
return;
}
level++;
for (int i = 0; i < input.count; i++)
{
if ([used[i] boolValue])
{
continue;
}
used[i] = [NSNumber numberWithBool:YES];
[output addObject:input[i]];
doPermute(input, output, used, size, level);
used[i] = [NSNumber numberWithBool:NO];
[output removeLastObject];
}
}
NSArray *getPermutations(NSString *input, int size)
{
results = [[NSMutableArray alloc] init];
NSMutableArray *chars = [[NSMutableArray alloc] init];
for (int i = 0; i < [input length]; i++)
{
NSString *ichar = [NSString stringWithFormat:#"%c", [input characterAtIndex:i]];
[chars addObject:ichar];
}
NSMutableArray *output = [[NSMutableArray alloc] init];
NSMutableArray *used = [[NSMutableArray alloc] init];
for (int i = 0; i < chars.count; i++)
{
[used addObject:[NSNumber numberWithBool:NO]];
}
doPermute(chars, output, used, size, 0);
return results;
}
-(double) factorialX: (int) num {
double tempResult = 1;
for (int i=2; i<=num; i++) {
tempResult *= i;
}
return tempResult;
}
/*=======================Call Like this====================
NSmutableArray=getPermutations("Pass your string", pass your lenght);
NsmutableArray=getPermutations("Janak", 2);
NSMutableArray=[self genValidWords:#"Hello"];
will return all possiable combination of two letters
=======================xxxxxxxxxx====================*/

Answer 3

I got the solution,
I want something like following.
-(NSArray*)totalWords:(NSArray*)letters
{
NSMutableArray *output=[[NSMutableArray alloc]init];
for (int i=0; i<letters.count; i++)
{
for (int j=0; j<letters.count; j++)
{
if (i==j) continue;
for (int k=0; k<letters.count; k++)
{
NSString *str=[NSString stringWithFormat:#"%#%#%#",letters[i],letters[j],letters[k]];
if(i!=j && j!=k && i!=k &&[self checkmeaning:str])
[output addObject:str];
for (int l=0; l<letters.count; l++)
{
NSString *str=[NSString stringWithFormat:#"%#%#%#%#",letters[i],letters[j],letters[k],letters[l]];
if(i!=j && j!=k && i!=k && l!=i && l!=j && l!=k &&[self checkmeaning:str])
[output addObject:str];
for (int m=0; m<letters.count; m++)
{
NSString *str=[NSString stringWithFormat:#"%#%#%#%#%#",letters[i],letters[j],letters[k],letters[l],letters[m]];
if(i!=j && j!=k && i!=k && l!=i && l!=j && l!=k && m!=i && m!=j && m!=k && m!=l &&[self checkmeaning:str])
[output addObject:str];
for (int n=0; n<letters.count; n++)
{
NSString *str=[NSString stringWithFormat:#"%#%#%#%#%#%#",letters[i],letters[j],letters[k],letters[l],letters[m],letters[n]];
if(i!=j && j!=k && i!=k && l!=i && l!=j && l!=k && m!=i && m!=j && m!=k && n!=i && n!=j && n!=k &&n!=m &&n!=l && m!=l&&[self checkmeaning:str])
[output addObject:str];
}
}
}
}
}
}
NSLog(#"count :%i",[output count]);
NSLog(#"output array :\n%#",output);
return output;
}