//============================================================================
// Name        : UniqueCharString.cpp
// Author      : Kevin Parks
// Version     : 1.0
// Copyright   : MIT License
// Description : Determines if a string contains all unique characters (ASCII)
//============================================================================

#include <iostream>
#include <vector>

#define TABLELEN (128)

/**
 *  \brief isUniqueCharString determines if a string has all unique characters
 *  \param str const reference to the std::string to check
 *  \return true if all chars are unique, false otherwise
 */
bool isUniqueCharString(const std::string &str)
{
	// First check if string is longer than ASCII chars, must have repeat if so
	// ASCII has 128 chars possible if you count everything
	if(str.length() >= TABLELEN)
		return false;

	// "hash" each character index. If the index has a 1 value, it's not unique
	int charTable[TABLELEN] = { 0 };
	for(unsigned i = 0; i < str.length(); ++i)
	{
		int curChar = (int)str[i];
		if(charTable[curChar] == 1)
		{
			// Value has been found before
			return false;
		}
		else
		{
			charTable[curChar] = 1;
		}
	}

	// Never found non-unique value
	return true;
}

int main() {
	std::cout << "UniqueCharString" << std::endl;
	std::vector<std::string> strings;
	strings.push_back("test");
	strings.push_back("abcd");
	strings.push_back("`1234567890-=qwertyuiop[]\\asdfghjkl;'zxcvbnm,./");
	for(unsigned i = 0; i < strings.size(); ++i)
	{
		if(isUniqueCharString(strings[i]))
		{
			std::cout << strings[i] << " has all unique characters" << std::endl;
		}
		else
		{
			std::cout << strings[i] << " does not have all unique characters" << std::endl;
		}
	}

	return 0;
}