//typescriptClasses/Algorithms.ts
//Matthew Ellison
// Created: 10-19-20
//Modified: 03-10-21
//This class holds many algorithms that I have found it useful to keep around
/*
Copyright (C) 2021  Matthew Ellison

	This program is free software: you can redistribute it and/or modify
	it under the terms of the GNU Lesser General Public License as published by
	the Free Software Foundation, either version 3 of the License, or
	(at your option) any later version.

	This program is distributed in the hope that it will be useful,
	but WITHOUT ANY WARRANTY; without even the implied warranty of
	MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
	GNU Lesser General Public License for more details.

	You should have received a copy of the GNU Lesser General Public License
	along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/


import { InvalidResult } from "./InvalidResult";


export function arrayEquals(array1: any[], array2: any[]): boolean{
	//If they aren't the same type they aren't equal
	if((typeof array1) != (typeof array2)){
		return false;
	}
	//If they aren't the same length they aren't equal
	else if(array1.length != array2.length){
		return false;
	}
	else{
		//Loop through every element to see if each one is equal
		for(let cnt = 0;cnt < array1.length;++cnt){
			//If any element in the same location is different return false
			if(array1[cnt] != array2[cnt]){
				return false;
			}
		}
		//If every element was the same they are equal
		return true;
	}
}

export function sqrtBig(value: bigint): bigint{
	if(value < 0n){
		throw "Negative numbers are not supported";
	}

	let k = 2n;
	let o = 0n;
	let x = value;
	let limit = 100;

	while(x ** k !== k && x !== o && --limit){
		o = x;
		x = ((k - 1n) * x + value / x ** (k - 1n)) / k;
	}

	return x;
}

export function getAllFib(goalNumber: number): number[]{
	//Setup the variables
	let fibNums: number[] = [];

	//If the number is <= 0 return an empty list
	if(goalNumber <= 0){
		return fibNums;
	}
	else if(goalNumber == 1){
		fibNums.push(1);
		return fibNums;
	}

	//This means that at least 2 1's are elements
	fibNums.push(1);
	fibNums.push(1);

	//Loop to generate the rest of the Fibonacci numbers
	while(fibNums[fibNums.length - 1] <= goalNumber){
		fibNums.push((fibNums[fibNums.length - 1]) + (fibNums[fibNums.length - 2]));
	}

	//At this point the most recent number is > goalNumber, so remove it and return the rest of the list
	fibNums.pop();
	return fibNums;
}
export function getAllFibBig(goalNumber: bigint): bigint[]{
	//Setup the variables
	let fibNums:bigint[] = [];

	//If the number is <= 0 return an empty list
	if(goalNumber <= 0){
		return fibNums;
	}
	else if(goalNumber == 1n){
		fibNums.push(1n);
		return fibNums;
	}

	//This means that at least 2 1's are elements
	fibNums.push(1n);
	fibNums.push(1n);

	//Loop to generate the rest of the Fibonacci numbers
	while(fibNums[fibNums.length - 1] <= goalNumber){
		fibNums.push((fibNums[fibNums.length - 1]) + (fibNums[fibNums.length - 2]));
	}

	//At this point the most recent number is > goalNumber, so remove it and return the rest of the list
	fibNums.pop();
	return fibNums;
}

export function getPrimes(goalNumber: number): number[]{
	let primes: number[] = [];	//Holds the prime numbers
	let foundFactor: boolean = false;	//A flag for whether a factor of the current number has been found

	//If the number is 0 or a negative return an empty list
	if(goalNumber <= 1){
		return primes;
	}
	//Optherwise the number is at least 2, so 2 should be added to the list
	else{
		primes.push(2);
	}

	//We can now start at 3 and skip all even numbers, because they cannot be prime
	for(let possiblePrime: number = 3;possiblePrime <= goalNumber;possiblePrime += 2){
		//Check all current primes, up to sqrt(possiblePrime), to see if there is a divisor
		let topPossibleFactor: number = Math.ceil(Math.sqrt(possiblePrime));
		//We can safely assume that there will be at least 1 element in the primes list because of 2 being added before this
		for(let primesCnt: number = 0;primes[primesCnt] <= topPossibleFactor;){
			if((possiblePrime % primes[primesCnt]) == 0){
				foundFactor = true;
				break;
			}
			else{
				++primesCnt;
			}
			//Check if the index has gone out of range
			if(primesCnt >= primes.length){
				break;
			}
		}

		//If you didn't find a factor then the current number must be prime
		if(!foundFactor){
			primes.push(possiblePrime);
		}
		else{
			foundFactor = false;
		}
	}

	//Sort the list before returning it
	primes = primes.sort((n1, n2) => n1 - n2);
	return primes;
}
export function getPrimesBig(goalNumber: bigint): bigint[]{
	let primes: bigint[] = [];	//Holds the prime numbers
	let foundFactor: boolean = false;	//A flag for whether a factor of the current number has been found

	//If the number is 0 or a negative return an empty list
	if(goalNumber <= 1){
		return primes;
	}
	//Optherwise the number is at least 2, so 2 should be added to the list
	else{
		primes.push(2n);
	}

	//We can now start at 3 and skip all even numbers, because they cannot be prime
	for(let possiblePrime: bigint = 3n;possiblePrime <= goalNumber;possiblePrime += 2n){
		//Check all current primes, up to sqrt(possiblePrime), to see if there is a divisor
		let topPossibleFactor: bigint = sqrtBig(possiblePrime);
		//We can safely assume that there will be at least 1 element in the primes list because of 2 being added before this
		for(let primesCnt: number = 0;primes[primesCnt] <= topPossibleFactor;){
			if((possiblePrime % primes[primesCnt]) == 0n){
				foundFactor = true;
				break;
			}
			else{
				++primesCnt;
			}
			//Check if the index has gone out of range
			if(primesCnt >= primes.length){
				break;
			}
		}

		//If you didn't find a factor then the current number must be prime
		if(!foundFactor){
			primes.push(possiblePrime);
		}
		else{
			foundFactor = false;
		}
	}

	//Sort the list before returning it
	primes = primes.sort(function(n1, n2){
		if(n1 > n2){
			return 1;
		}
		else if(n1 < n2){
			return -1;
		}
		else{
			return 0;
		}
	});
	return primes;
}

export function getNumPrimes(numberOfPrimes: number): number[]{
	let primes: number[] = [];	//Holds the prime numbers
	let foundFactor: boolean = false;	//A flag for whether a factor of the current number has been found

	//If the number is 0 or negative return an empty list
	if(numberOfPrimes <= 1){
		return primes;
	}
	//Otherwise the number is at least 2, so 2 should be added to the list
	else{
		primes.push(2);
	}

	//We can now start at 3 and skip all even number, because they cannot be prime
	for(let possiblePrime: number = 3;primes.length < numberOfPrimes;possiblePrime += 2){
		//Check all the current primes, up to sqrt(possiblePrime), to see if there is a divisor
		let topPossibleFactor: number = Math.ceil(Math.sqrt(possiblePrime));
		//We can safely assume that there will be at least 1 element in the primes list because of 2 being added by default
		for(let primesCnt: number = 0;primes[primesCnt] <= topPossibleFactor;){
			if((possiblePrime % primes[primesCnt]) == 0){
				foundFactor = true;
				break;
			}
			else{
				++primesCnt;
			}
			//Check if the index has gone out of bounds
			if(primesCnt >= primes.length){
				break;
			}
		}

		//If you didn't find a factor then the current number must be prime
		if(!foundFactor){
			primes.push(possiblePrime);
		}
		else{
			foundFactor = false;
		}
	}

	//Sort the list before returning it
	primes = primes.sort((n1, n2) => n1 - n2);
	return primes;
}
export function getNumPrimesBig(numberOfPrimes: bigint): bigint[]{
	let primes: bigint[] = [];	//Holds the prime numbers
	let foundFactor: boolean = false;	//A flag for whether a factor of the current number has been found

	//If the number is 0 or negative return an empty list
	if(numberOfPrimes <= 1){
		return primes;
	}
	//Otherwise the number is at least 2, so 2 should be added to the list
	else{
		primes.push(2n);
	}

	//We can now start at 3 and skip all even number, because theyu cannot be prime
	for(let possiblePrime: bigint = 3n;primes.length < numberOfPrimes;possiblePrime += 2n){
		//Check all the current primes, up to sqrt(possiblePrime), to see if there is a divisor
		let topPossibleFactor: bigint = sqrtBig(possiblePrime);
		//We can safely assume that ther ewill be at least 1 element in the primes list because of 2 being added by default
		for(let primesCnt: number = 0;primes[primesCnt] <= topPossibleFactor;){
			if((possiblePrime % primes[primesCnt]) == 0n){
				foundFactor = true;
				break;
			}
			else{
				++primesCnt;
			}
			//Check if the index has gone out of bounds
			if(primesCnt >= primes.length){
				break;
			}
		}

		//If you didn't find a factor then the current number must be prime
		if(!foundFactor){
			primes.push(possiblePrime);
		}
		else{
			foundFactor = false;
		}
	}

	//Sort the list before returning it
	primes = primes.sort(function(n1, n2){
		if(n1 > n2){
			return 1;
		}
		else if(n1 < n2){
			return -1;
		}
		else{
			return 0;
		}
	});
	return primes;
}

export function isPrime(possiblePrime: number): boolean{
	if(possiblePrime <= 3){
		return possiblePrime > 1;
	}
	else if(((possiblePrime % 2) == 0) || ((possiblePrime % 3) == 0)){
		return false;
	}
	for(let cnt: number = 5;(cnt * cnt) <= possiblePrime; cnt += 6){
		if(((possiblePrime % cnt) == 0) || ((possiblePrime % (cnt + 2)) == 0)){
			return false;
		}
	}
	return true;
}
export function isPrimeBig(possiblePrime: bigint): boolean{
	if(possiblePrime <= 3n){
		return possiblePrime > 1n;
	}
	else if(((possiblePrime % 2n) == 0n) || ((possiblePrime % 3n) == 0n)){
		return false;
	}
	for(let cnt : bigint = 5n;(cnt * cnt) <= possiblePrime;cnt += 6n){
		if(((possiblePrime % cnt) == 0n) || ((possiblePrime % (cnt + 2n)) == 0n)){
			return false;
		}
	}
	return true;
}

export function getFactors(goalNumber: number): number[]{
	//You need to get all the primes that could be factors of this number so you can test them
	let topPossiblePrime: number = Math.ceil(Math.sqrt(goalNumber));
	let primes: number[] = getPrimes(topPossiblePrime);
	let factors: number[] = [];

	//You need to step through each prime and see if it is a factor in the number
	for(let cnt: number = 0;cnt < primes.length;){
		//If the prime is a factor you need to add it to the factor list
		if((goalNumber % primes[cnt]) == 0){
			factors.push(primes[cnt]);
			goalNumber /= primes[cnt];
		}
		//Otherwise advance the location in primes you are looking at
		//By not advancing f the prime is a factor you allow for multiple of the same prime number as a factor
		else{
			++cnt;
		}
	}

	//If you didn't get any factors the number itself must be a prime
	if(factors.length == 0){
		factors.push(goalNumber);
		goalNumber /= goalNumber;
	}

	//If for some reason the goalNumber is not 1 throw an exception
	if(goalNumber != 1){
		throw new InvalidResult("The factor was not 1: " + goalNumber);
	}

	//Return the list of factors
	return factors;
}
export function getFactorsBig(goalNumber: bigint): bigint[]{
	//You need to get all the primes that could be factors of this number so you can test them
	let topPossiblePrime: bigint = sqrtBig(goalNumber);
	let primes: bigint[] = getPrimesBig(topPossiblePrime);
	let factors: bigint[] = [];

	//You need to step through each prime and see if it is a factor in the number
	for(let cnt: number = 0;cnt < primes.length;){
		//If the prime is a factor you need to add it to the factor list
		if((goalNumber % primes[cnt]) == 0n){
			factors.push(primes[cnt]);
			goalNumber /= primes[cnt];
		}
		//Otherwise advance the location in primes you are looking at
		//By not advancing f the prime is a factor you allow for multiple of the same prime number as a factor
		else{
			++cnt;
		}
	}

	//If you didn't get any factors the number itself must be a prime
	if(factors.length == 0){
		factors.push(goalNumber);
		goalNumber /= goalNumber;
	}

	//If for some reason the goalNumber is not 1 throw an exception
	if(goalNumber != 1n){
		throw new InvalidResult("The factor was not 1: " + goalNumber);
	}

	//Return the list of factors
	return factors;
}

export function getDivisors(goalNumber: number): number[]{
	let divisors: number[] = [];

	//Start by checking that the number is positive
	if(goalNumber <= 0){
		return divisors;
	}
	//If the number is 1 return just itself
	else if(goalNumber == 1){
		divisors.push(1);
		return divisors;
	}

	//Start at 3 and loop through all numbers < sqrt(goalNumber) looking for a number that divides it evenly
	let topPossibleDivisor: number = Math.ceil(Math.sqrt(goalNumber));
	for(let possibleDivisor = 1;possibleDivisor <= topPossibleDivisor;++possibleDivisor){
		//If you find one add it and the number it creates to the list
		if((goalNumber % possibleDivisor) == 0){
			divisors.push(possibleDivisor);
			//Account for the possibility of sqrt(goalNumber) being a divisor
			if(possibleDivisor != topPossibleDivisor){
				divisors.push(goalNumber / possibleDivisor);
			}
			if(divisors[divisors.length - 1] == (possibleDivisor + 1)){
				++possibleDivisor;
			}
		}
	}

	//Sort the list before returning it for neatness
	divisors.sort((a, b) => a - b);
	//Return the list
	return divisors;
}
export function getDivisorsBig(goalNumber: bigint): bigint[]{
	let divisors: bigint[] = [];

	//Start by checking that the number is positive
	if(goalNumber <= 0n){
		return divisors;
	}
	//If the number is 1 return just itself
	else if(goalNumber == 1n){
		divisors.push(1n);
		return divisors;
	}

	//Start at 3 and loop through all numbers < sqrt(goalNumber) looking for a number that divides it evenly
	let topPossibleDivisor: bigint = sqrtBig(goalNumber);
	for(let possibleDivisor = 1n;possibleDivisor <= topPossibleDivisor;++possibleDivisor){
		//If you find one add it and the number it creates to the list
		if((goalNumber % possibleDivisor) == 0n){
			divisors.push(possibleDivisor);
			//Account for the possibility of sqrt(goalNumber) being a divisors
			if(possibleDivisor != topPossibleDivisor){
				divisors.push(goalNumber / possibleDivisor);
			}
			if(divisors[divisors.length - 1] == (possibleDivisor + 1n)){
				++possibleDivisor;
			}
		}
	}

	//Sort the list before returning it for neatness
	divisors.sort((a, b) => {
		if(a > b){
			return 1;
		}
		else if(a < b){
			return -1;
		}
		else{
			return 0;
		}
	});
	//Return the list
	return divisors;
}

export function getSum(ary: number[]): number{
	let sum: number = 0;
	ary.forEach(a => sum += a);
	return sum;
}
export function getSumBig(ary: bigint[]): bigint{
	let sum: bigint = 0n;
	ary.forEach(a => sum += a);
	return sum;
}
export function getProd(ary: number[]): number{
	//Return 0 if the array is empty
	if(ary.length == 0){
		return 0;
	}

	let prod: number = 1;
	ary.forEach(a => prod *= a);
	return prod;
}
export function getProdBig(ary: bigint[]): bigint{
	//Return 0 if the array is empty
	if(ary.length == 0){
		return 0n;
	}

	let prod: bigint = 1n;
	ary.forEach(a => prod *= a);
	return prod;
}

export function getFib(goalSubscript: number): number{
	//Setup the variables
	let fibNums: number[] = [1, 1, 0];	//A list to keep track of the Fibonacci numbers. It need only be 3 long because we only need the one we are working on and the last 2

	//If the number is <= 0 return 0
	if(goalSubscript <= 0){
		return 0;
	}

	//Loop through the list, generating Fibonacci numbers until it finds the correct subscript
	let fibLoc: number = 2;
	for(fibLoc = 2;fibLoc < goalSubscript;++fibLoc){
		fibNums[fibLoc % 3] = fibNums[(fibLoc - 1) % 3] + fibNums[(fibLoc - 2) % 3];
	}

	//Return the proper number. The location counter is 1 off of the subscript
	return fibNums[(fibLoc - 1) % 3];
}
export function getFibBig(goalSubscript: bigint): bigint{
	//Setup the varibles
	let fibNums: bigint[] = [1n, 1n, 0n];	//A list to keep track of the Fibonacci numbers. It need only be 3 long because we only need the one we are working on and the last 2

	//If the number is <= 0 return 0
	if(goalSubscript <= 0n){
		return 0n;
	}

	//Loop through the list, generating Fibonacci numbers until it finds the correct subscript
	let fibLoc: bigint = 2n;
	for(fibLoc = 2n;fibLoc < goalSubscript;++fibLoc){
		fibNums[Number(fibLoc % 3n)] = fibNums[Number((fibLoc - 1n) % 3n)] + fibNums[Number((fibLoc - 2n) % 3n)];
	}

	//Return the proper number. The location counter is 1 off of the subscript
	return fibNums[Number((fibLoc - 1n) % 3n)];
}

//This is a function that creates all permutations of a string and returns a vector of those permutations
export function getPermutations(master: string): string[]{
	return getPermutationsHelper(master, 0);
}
function getPermutationsHelper(master: string, num: number): string[]{
	let perms: string[] = [];
	//Check if the number is out of bounds
	if((num >= master.length) || (num < 0)){
		//Do nothing and return an empty array
	}
	//If this is the last possible recurse just return the current string
	else if(num == (master.length - 1)){
		perms.push(master);
	}
	//If there are more possible recurses, recurse with the current permutation
	else{
		let temp: string[] = getPermutationsHelper(master, num + 1);
		temp.forEach(str => perms.push(str));
		//You need to swap the current letter with every possible letter after it
		//The ones needed to swap before will happen automatically when the function recurses
		for(let cnt = 1;(num + cnt) < master.length;++cnt){
			master = swapString(master, num, (num + cnt));
			temp = getPermutationsHelper(master, num + 1);
			temp.forEach(str => perms.push(str));
			master = swapString(master, num, (num + cnt));
		}

		//The array is not necessarily in alph-numeric order. So if this is the full array sort it before returning
		if(num == 0){
			perms.sort();
		}
	}

	//Return the array that was build
	return perms;
}
function swapString(str: string, first: number, second: number): string{
	let tempStr: string = str.substr(0, first) + str[second] + str.substr(first + 1, second - first - 1) + str[first] + str.substr(second + 1);

	return tempStr;
}

//This function returns the number of times the character occurs in the string
export function findNumOccurrence(str: string, ch: string){
	let num: number = 0;	//Set the number of occurrences to 0 to start
	//Loop through every character in the string and compare it to the character passed in
	for(let strCh of str){
		//If the character is the same as the one passed in increment the counter
		if(strCh == ch){
			++num;
		}
	}
	//Return the number of times the character appeared in the string
	return num;
}