I have coded Boyer-Moore horspool string matching algorithm using node.js. The program works, but always outputs -1, which is what it should output if the pattern string is not in the specified text.
I am unable to figure out for the life of me what isn't working, and I would be most appreciative of a hint for what I need to fix.
My code
var horsPool = function(sText,sPattern)
{
var m = sPattern.length;
var n = sText.length;
var i = m - 1;
while(i<=n-1)
{
var k = 0;
while ((k <= m) && (sPattern[m - 1 - k]) == sText[i - k])
{
k++;
}
if(k==m)
{
return (i - m + 1);
}
else
{
i += t[sText[i]];
}
}
return -1;
}
var shiftTable = function (sPat)
{
var i;
var j;
var m;
m = sPat.length;
for(i=0; i < MAX; i++)
{
t[i] = m;
}
for (j = 0; j<m-2; j++)
{
t[sPat[j]] = m-1 -j;
}
}
var program = function()
{
var text = 'lklkababcabab';
var pattern = 'ka';
shiftTable(pattern);
var pos = horsPool(text,pattern);
if(pos >= 0)
console.log('Pattern found in %d',pos);
else
console.log('Pattern not found');
}
var MAX = new Array(256);
var t = [MAX];
program();
Any help would be greatly appreciated. Thank You!
Let's start from down under:
var MAX = new Array(256);
var t = [MAX];
does not work at all. The first line initiates an array with 256 empty entries, the second line initiates an array with one element: the array build in the line above. That's not what you wanted to do, I presume. So
var MAX = 256;
var t = new Array(MAX);
does what you want.
The lines with t[sPat[j]] and t[sText[i]] will not work as expected, because sText[i] and sPat[j] return a character instead of a number. You might give t[sPat.charCodeAt(j)] and t[sText.charCodeAt(i)] a try.
To give you a start without helping too much, here is a straight-forward implementation of the algorithm given at Wikipedia:
var horsPool = function (haystack, needle)
{
var nl = needle.length;
var hl = haystack.length;
var skip = 0;
while (hl - skip >= nl)
{
var i = nl - 1;
while (haystack[skip + i] == needle[i])
{
if (i == 0) {
return skip;
}
i--;
}
skip = skip + t[haystack.charCodeAt(skip + nl - 1)];
}
return - 1;
}
var shiftTable = function (pattern)
{
for (var i = 0; i < MAX; i++) {
t[i] = pattern.length;
}
for (var i = 0; i < pattern.length - 1; i++) {
t[pattern.charCodeAt(i)] = pattern.length - 1 - i;
}
}
var program = function ()
{
var text = 'lklkababcabab';
var pattern = 'kab';
shiftTable(pattern);
var pos = horsPool(text, pattern);
if (pos >= 0)
console.log('Pattern found in %d', pos);
else
console.log('Pattern not found');
}
var MAX = 256;
var t = new Array(256);
program();
Related
I have the following javascript code to calculate the factors of numbers.
var some = [];
var main = "";
var final = "";
function text(data) {
spliter = data.split(",");
var k = 0;
while (k < spliter.length) {
var meethi = 0;;
main = spliter[k];
var datas = "";
for (var i = 1; i <= 10; i += 1) {
meethi = Math.abs(main / i);
datas = meethi;
some.push('' + datas + '');
}
some.forEach(myFunction);
final += res + '<br>';
k++;
}
return final;
}
var max = 0;
var res = "";
function myFunction(item) {
var van = item.split(".");
if (van[1] == undefined) {
var high = Math.floor(main / van[0]);
if (high > max) {
max = high;
res += max + ':';
}
}
}
document.getElementById('demo').innerHTML = text('124,20');
<p id="demo"></p>
My program gets the factors with two values. How do I identify the common factor of both values,only the highest common value?
example like ('124,20') output --> 4
I tried the code with my own knowledge. If you have any other suggestion for code please tell me and correct my code with my desired result.
my fiddle
You could use for the greatest common divisor Euclid's algorithm.
function gcd(k, n) {
return k ? gcd(n % k, k) : n;
}
console.log(gcd(124, 20));
console.log([10, 500, 600].reduce(gcd));
I'm trying to do, binary search using Javascript, everything is working fine, but I'm unable to console(display) the undefined value(I want to print 'the number is not in the list' if the item is not in the list.)
Thanks in advance.
Here is my code:
function bSearch(userInput, numb){
//var inputSplit = userInput.toString().split('');
var input = numSort(userInput);
//console.log(input);
var start = 0;
var n = input.length;
//console.log(n);
var end = n-1;
var output = '';
//var mid = (start + end) / 2;
// console.log(mid);
while(start <= end){
var mid = (start + end) / 2;
mid = Math.floor(mid);
//console.log(mid);
if(input[mid] == numb){
output = input[mid];
return output;
}else if(numb < input[mid]){
end = mid - 1;
}else if(numb > input[mid]){
start = mid + 1;
}
}
}
function numSort(num){
var temp = '';
var res = '';
arr = num.toString().split('');
var n = arr.length;
for(i=0; i<n-1; i++){
for(d=0; d<n-i-1; d++){
if(arr[d] > arr[d+1]){
temp = arr[d];
arr[d] = arr[d+1];
arr[d+1] = temp;
}
}
}
for(i=0; i<n; i++){
res += arr[i];
}return res;
}
Add the return statement at the end of the function
function bSearch(userInput, numb) {
// lots of code (some vars without declarations ...)
// ...
return 'the number is not in the list';
}
This is preventing undefined. Instead it is returning the string.
I'm creating a form where users can input a range. They are allowed to input letters and numbers. Some sample input:
From: AA01
To: AZ02
Which should result in:
AA01
AA02
AB01
AB02
And so on, till AZ02
And:
From: BC01
To: DE01
Should result in:
BC01
BD01
BE01
CC01
CD01
CE01
Etc
I managed to get it working for the input A01 to D10 (for example)
jsFiddle
However, i can't get it to work with multiple letters.
JS code:
var $from = $('input[name="from"]');
var $to = $('input[name="to"]');
var $quantity = $('input[name="quantity"]');
var $rangeList = $('.rangeList');
var $leadingzeros = $('input[name="leadingzeros"]');
$from.on('keyup blur', function () {
$(this).val($(this).val().replace(/[^a-zA-Z0-9]/g, ''));
updateQuantity();
});
$to.on('keyup blur', function () {
$(this).val($(this).val().replace(/[^a-zA-Z0-9]/g, ''));
updateQuantity();
});
$leadingzeros.on('click', function () {
updateQuantity();
});
function updateQuantity() {
var x = parseInt($from.val().match(/\d+/));
var y = parseInt($to.val().match(/\d+/));
var xl = $from.val().match(/[a-zA-Z]+/);
var yl = $to.val().match(/[a-zA-Z]+/);
var result = new Array();
if (xl != null && yl != null && xl[0].length > 0 && yl[0].length > 0) {
xl = xl[0].toUpperCase();
yl = yl[0].toUpperCase();
$rangeList.html('');
var a = yl.charCodeAt(0) - xl.charCodeAt(0);
for (var i = 0; i <= a; i++) {
if (!isNaN(x) && !isNaN(y)) {
if (x <= y) {
var z = (y - x) + 1;
$quantity.val(z * (a + 1));
$rangeList.html('');
for (var b = z; b > 0; b--) {
var c = ((y - b) + 1);
if ($leadingzeros.prop('checked')) {
c = leadingZeroes(c, y.toString().length);
}
result.push(String.fromCharCode(65 + i) + c);
}
} else {
$rangeList.html('');
$quantity.val(0);
}
} else {
$rangeList.html('');
$quantity.val(0);
}
}
} else if (!isNaN(x) && !isNaN(y)) {
if (x < y) {
var z = (y - x) + 1;
$quantity.val(z);
$rangeList.html('');
for (var i = z; i > 0; i--) {
var c = (y - i) + 1;
if ($leadingzeros.prop('checked')) {
c = leadingZeroes(c, y.toString().length);
}
result.push(c);
}
} else {
$rangeList.html('');
$quantity.val(0);
}
} else {
$rangeList.html('');
$quantity.val(0);
}
$rangeList.html('');
for (var i = 0; i < result.length; i++) {
$rangeList.append(result[i] + '<br />');
}
}
function leadingZeroes(number, size) {
number = number.toString();
while (number.length < size) number = "0" + number;
return number;
}
This is perfect for a recursive algorithm:
function createRange(from, to) {
if (from.length === 0) {
return [ "" ];
}
var result = [];
var innerRange = createRange(from.substring(1), to.substring(1));
for (var i = from.charCodeAt(0); i <= to.charCodeAt(0); i++) {
for (var j = 0; j < innerRange.length; j++) {
result.push(String.fromCharCode(i) + innerRange[j]);
}
}
return result;
}
Called as follows:
createRange('BC01', 'DE02'); // Generates an array containing all values expected
EDIT: Amended function below to match new test case (much more messy, however, involving lots of type coercion between strings and integers).
function prefixZeroes(value, digits) {
var result = '';
value = value.toString();
for (var i = 0; i < digits - value.length; i++) {
result += '0';
}
return result + value;
}
function createRange(from, to) {
if (from.length === 0) {
return [ "" ];
}
var result = [];
if (from.charCodeAt(0) < 65) {
fromInt = parseInt(from);
toInt = parseInt(to);
length = toInt.toString().length;
var innerRange = createRange(from.substring(length), to.substring(length));
for (var i = fromInt; i <= toInt; i++) {
for (var j = 0; j < innerRange.length; j++) {
result.push(prefixZeroes(i, length) + innerRange[j]);
}
}
} else {
var innerRange = createRange(from.substring(1), to.substring(1));
for (var i = from.charCodeAt(0); i <= to.charCodeAt(0); i++) {
for (var j = 0; j < innerRange.length; j++) {
result.push(String.fromCharCode(i) + innerRange[j]);
}
}
}
return result;
}
Please note that because of your strict logic in how the value increments this method requires exactly 4 characters (2 letters followed by 2 numbers) to work. Also, this might not be as efficient/tidy as it can be but it took some tinkering to meet your logic requirements.
function generate(start, end) {
var results = [];
//break out the start/end letters/numbers so that we can increment them seperately
var startLetters = start[0] + start[1];
var endLetters = end[0] + end[1];
var startNumber = Number(start[2] + start[3]);
var endNumber = Number(end[2] + end[3]);
//store the start letter/number so we no which value to reset the counter to when a maximum boundry in reached
var resetLetter = startLetters[1];
var resetNumber = startNumber;
//add first result as we will always have at least one
results.push(startLetters + (startNumber < 10 ? "0" + startNumber : "" + startNumber));
//maximum while loops for saefty, increase if needed
var whileSafety = 10000;
while (true) {
//safety check to ensure while loop doesn't go infinite
whileSafety--;
if (whileSafety == 0) break;
//check if we have reached the maximum value, if so stop the loop (break)
if (startNumber == endNumber && startLetters == endLetters) break;
//check if we have reached the maximum number. If so, and the letters limit is not reached
//then reset the number and increment the letters by 1
if (startNumber == endNumber && startLetters != endLetters) {
//reset the number counter
startNumber = resetNumber;
//if the second letter is at the limit then reset it and increment the first letter,
//otherwise increment the second letter and continue
if (startLetters[1] == endLetters[1]) {
startLetters = '' + String.fromCharCode(startLetters.charCodeAt(0) + 1) + resetLetter;
} else {
startLetters = startLetters[0] + String.fromCharCode(startLetters.charCodeAt(1) + 1);
}
} else {
//number limit not reached so just increment the number counter
startNumber++;
}
//add the next sequential value to the array
results.push(startLetters + (startNumber < 10 ? "0" + startNumber : "" + startNumber));
}
return results;
}
var results = generate("BC01", "DE01");
console.log(results);
Here is a working example, which uses your second test case
Using #Phylogenesis' code, i managed to achieve my goal.
jsFiddle demo
function updateQuantity() {
var x = parseInt($from.val().match(/\d+/));
var y = parseInt($to.val().match(/\d+/));
var xl = $from.val().match(/[a-zA-Z]+/);
var yl = $to.val().match(/[a-zA-Z]+/);
var result = new Array();
var r = createRange(xl[0], yl[0]);
var z = (y - x) + 1;
if (x <= y) {
for (var j = 0; j < r.length; j++) {
var letters = r[j];
for (var i = z; i > 0; i--) {
var c = (y - i) + 1;
if ($leadingzeros.prop('checked')) {
c = leadingZeroes(c, y.toString().length);
}
if (i == z) {
r[j] = letters + c + '<br />';
} else {
j++;
r.splice(j, 0, letters + c + '<br />');
}
}
}
} else {
for (var i = 0; i < r.length; i++) {
r[i] += '<br />';
}
}
$quantity.val(r.length);
$rangeList.html('');
for (var i = 0; i < r.length; i++) {
$rangeList.append(r[i]);
}
}
This works for unlimited letters and numbers, as long as the letters are first.
Thanks for your help!
How can I check for matching numbers in this script, stuck here, I need to compare the array of user numbers with the array of lotto numbers and display how many numbers they got correct if any along with their prize value.
function numbers() {
var numbercount = 6;
var maxnumbers = 40;
var ok = 1;
r = new Array(numbercount);
for (var i = 1; i <= numbercount; i++) {
r[i] = Math.round(Math.random() * (maxnumbers - 1)) + 1;
}
for (var i = numbercount; i >= 1; i--) {
for (var j = numbercount; j >= 1; j--) {
if ((i != j) && (r[i] == r[j])) ok = 0;
}
}
if (ok) {
var output = "";
for (var k = 1; k <= numbercount; k++) {
output += r[k] + ", ";
}
document.lotto.results.value = output;
} else numbers();
}
function userNumbers() {
var usersNumbers = new Array(5);
for (var count = 0; count <= 5; count++) {
usersNumbers[count] = window.prompt("Enter your number " + (count + 1) + ": ");
}
document.lotto.usersNumbers.value = usersNumbers;
}
Here is a lotto numbers generator and a scoring system. I'm going to leave it to you to validate the user input.
function lottoGen(){
var lottoNumbers = [];
for(var k = 0; k<6; k++){
var num = Math.floor(Math.random()*41);
if(lottoNumbers.indexOf(num) != -1){
lottoNumbers.push(num);
}
}
return lottoNumbers;
}
function scoreIt(){
var usersNumbers = document.getElementsByName('usersNumbers').item(0);
usersNumbers = String(usersNumbers)
usersNumbers = usersNumbers.split(' ');
var matches = 0;
for(var i = 0; i<6; i++){
if(lottoNumbers.indexOf(usersNumbers[i]) != -1){matches++;}
}
return matches;
}
Hi I'm new to this and trying to learn off my own back so obviously I'm no expert but the code above makes a lot of sense to me, apart from the fact I can't get it to work.. I tried to console.log where it says RETURN so I could see the numbers but it just shows an empty array still. I assumed this was to do with it being outside the loop..
I've tried various ways but the best I get is an array that loops the same number or an array with 6 numbers but some of which are repeated..
function lottoGen(){
var lottoNumbers = [];
for(var k = 0; k<6; k++){
var num = Math.floor(Math.random()*41);
if(lottoNumbers.indexOf(num) != -1){
lottoNumbers.push(num);
}
}
return lottoNumbers;
}
Lotto JS: CODEPEN DEMO >> HERE <<
(function(){
var btn = document.querySelector("button");
var output = document.querySelector("#result");
function getRandom(min, max){
return Math.round(Math.random() * (max - min) + min);
}
function showRandomNUmbers(){
var numbers = [],
random;
for(var i = 0; i < 6; i++){
random = getRandom(1, 49);
while(numbers.indexOf(random) !== -1){
console.log("upps (" + random + ") it is in already.");
random = getRandom(1, 49);
console.log("replaced with: (" + random + ").");
}
numbers.push(random);
}
output.value = numbers.join(", ");
}
btn.onclick = showRandomNUmbers;
})();
I need a function which can transform the number 10000 to this number: 10.000.
So I tried the following:
function formatMoney(money){
var value = money.toString();
var l = value.length;
var new_value = 0;
new_value = new_value.toString();
if(l > 3){
var moneyarray = value.split('');
var u = 0;
for(i = l;i >= 0;i--){
if(u > 3){
u = 0;
new_value = "."+new_value;
}
new_value = moneyarray[i]+new_value;
u++;
}
}
return new_value;
}
And then call this:
formatMoney("10000");
But the result is
10.000undefined0"
What did I do wrong?
You're assigning the index counter to the length of the string;
var l = value.length;
...
for(i = l;i >= 0;i--){
And the down count starts with the length-index, which isn't present since arrays are zero-based. Subtract beforehand instead;
for(i = l;i >= 0;--i){
EDIT: Disregard this, I wasn't paying enough attention to the question.
If all you're looking to do is take numbers that are 4 digits or greater and put a dot in three digits from the right, you could give this a shot:
function formatMoney(money) {
var moneyString = money.toString();
var moneyLength = moneyString.length;
if(moneyLength < 4) {
return 0;
}
var dotIndex = moneyLength - 3;
return moneyString.substr(0, dotIndex) + "." + moneyString.substr(dotIndex);
}
Also, formatting your code in the post is good stuff. Indent it all by four spaces.
function formatMoney(money){
var value = money.toString();
var l = value.length;
var new_value = 0;
new_value = new_value.toString();
if(l > 3){
var moneyarray = value.split('');
for(var i = l-1;i >= 0;i--){
if((l-i)%3 === 0){
new_value = "."+new_value;
}
new_value = moneyarray[i]+new_value;
}
} else {
new_value = value;
}
return new_value;
}
A couple of things:
You were counting down with the wrong index (you were starting at l, instead of l-1)
You were not handling any value less than 1000
You don't need to use a counter variable u, you can just use modulo math to keep track of threes.
I cut off some parts:
function formatMoney(money) {
var value = money.toString();
var l = value.length;
var new_value = "";
if (l > 3) {
var u = 0;
for (i = l-1;i >= 0;i--) {
if (u == 3) {
u = 0;
new_value = "." + new_value;
}
new_value = value[i]+new_value;
u++;
}
}
return new_value;
}
You could do it like this:
function money(m) {
m = m.toString().split('');
for (var i = m.length - 3; i > 0; i -= 3)
m.splice(i,0,".");
return m.join('');
}
console.log(money(1000000)); // "1.000.000
See this JsBin