gistfile1.txt

-(NSNumber*)numberOfPairs:(NSArray*) a joinArg2:(NSNumber*) k {
    //No of Pairs
    int nop=0;
    int sumNumber =[k intValue];
    //Checking to see if the sum can be perfectly halved so as to avoid an issues with removing duplicates
    if ((sumNumber % 2) == 0){
        //No of occurence of half of sum number to be tested
        int noSameDivNo=0;
        NSMutableArray *testArrayModified=[[NSMutableArray alloc] init];
        NSMutableArray *testArray=[[NSMutableArray alloc] initWithArray:a];
        for (int i=0; i<[testArray count]; i++) {
            if (!([[testArray objectAtIndex:i] intValue]==sumNumber/2)) {
                //Modifying the array
                [testArrayModified addObject:[testArray objectAtIndex:i]];
                
            }else{
                noSameDivNo++;
            }
        }
        //Removing multiple occurances of same pair
        testArrayModified=[[NSMutableArray alloc] initWithArray:[[NSSet setWithArray:testArrayModified] allObjects]];
        
        for (int i=0; i<[testArrayModified count]; i++) {
            
            for (int j=0; j<[testArrayModified count]; j++) {
                if ((([[testArrayModified objectAtIndex:i] intValue])+([[testArrayModified objectAtIndex:j] intValue]))==sumNumber) {
                    nop++;
                }
            }
        }
        
        //Checking for multiple halves of sum number
        if (noSameDivNo>=2) {
            return [NSNumber numberWithInt:nop/2+1];
        }else{
            return [NSNumber numberWithInt:nop/2];
        }

    }else{
        NSMutableArray *testArray=[[NSMutableArray alloc] initWithArray:[[NSSet setWithArray:a] allObjects]];
        for (int i=0; i<[testArray count]; i++) {
            
            for (int j=0; j<[testArray count]; j++) {
                if ((([[testArray objectAtIndex:i] intValue])+([[testArray objectAtIndex:j] intValue]))==sumNumber) {
                    nop++;
            
                }
            }

        }
        
        return [NSNumber numberWithInt:nop/2];
    }
}