Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

updated the kmp from es5->es6 #214

Open
wants to merge 1 commit into
base: master
Choose a base branch
from
Open

updated the kmp from es5->es6 #214

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
65 changes: 31 additions & 34 deletions src/searching/knuth-morris-pratt.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,14 +1,17 @@
(function (exports) {
'use strict';

var kmp = (function () {
function builtKMPTable(str) {
var res = [];
var len;
var front;
var end;
var found;
for (var i = 1; i <= str.length; i += 1) {
const kmp = (str, substr) => {
if (str === substr) {
return 0;
}
const builtKMPTable = (str) => {
const res = [];
let len;
let front;
let end;
let found;
for (let i = 1; i <= str.length; i += 1) {
front = Math.max(1, i - ((res[i - 2] || 0) + 1));
end = Math.min(i - 1, (res[i - 2] || 0) + 1);
found = false;
Expand All @@ -25,7 +28,7 @@
res[i - 1] = len;
}
return res;
}
};

/**
* Knuth–Morris–Pratt algorithm. Searches for the position of
Expand All @@ -45,35 +48,29 @@
* where the specified substring occurs for the first
* time, or -1 if it never occurs.
*/
function indexOf(str, substr) {
if (str === substr) {
return 0;

const table = builtKMPTable(substr);
let i = 0;
let j = 0;
while (i < str.length) {
if (str[i] === substr[j]) {
i += 1;
j += 1;
}
var table = builtKMPTable(substr);
var i = 0;
var j = 0;
while (i < str.length) {
if (str[i] === substr[j]) {
if (j === substr.length) {
return i - j;
}
if (i < str.length && str[i] !== substr[j]) {
if (j > 0 && table[j - 1] !== 0) {
j = table[j - 1];
} else {
i += 1;
j += 1;
}
if (j === substr.length) {
return i - j;
}
if (i < str.length && str[i] !== substr[j]) {
if (j > 0 && table[j - 1] !== 0) {
j = table[j - 1];
} else {
i += 1;
j = 0;
}
j = 0;
}
}
return -1;
}
return indexOf;
}());

return -1;
};
exports.kmp = kmp;

})(typeof window === 'undefined' ? module.exports : window);