84 lines
2.4 KiB
JavaScript
84 lines
2.4 KiB
JavaScript
// Permutations in js reference (also cool algorithm):
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// https://stackoverflow.com/a/41068709
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function perm(a){
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if (a.length == 0) return [[]];
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var r = [[a[0]]],
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t = [],
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s = [];
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if (a.length == 1) return r;
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for (var i = 1, la = a.length; i < la; i++){
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for (var j = 0, lr = r.length; j < lr; j++){
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r[j].push(a[i]);
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t.push(r[j]);
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for(var k = 1, lrj = r[j].length; k < lrj; k++){
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for (var l = 0; l < lrj; l++) s[l] = r[j][(k+l)%lrj];
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t[t.length] = s;
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s = [];
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}
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}
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r = t;
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t = [];
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}
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return r;
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}
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function setText(id, text) {
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document.getElementById(id).textContent = text;
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}
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function setHTML(id, html) {
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document.getElementById(id).innerHTML = html;
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}
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function setValue(id, value) {
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let el = document.getElementById(id);
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el.value = value;
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el.dispatchEvent(new Event("change"));
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}
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// Base 64 encoding tools
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// https://stackoverflow.com/a/27696695
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// Modified for fixed precision
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Base64 = (function () {
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var digitsStr =
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// 0 8 16 24 32 40 48 56 63
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// v v v v v v v v v
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"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz+-";
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var digits = digitsStr.split('');
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var digitsMap = {};
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for (var i = 0; i < digits.length; i++) {
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digitsMap[digits[i]] = i;
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}
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return {
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fromIntV: function(int32) {
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var result = '';
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while (true) {
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result = digits[int32 & 0x3f] + result;
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int32 >>>= 6;
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if (int32 === 0)
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break;
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}
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return result;
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},
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fromIntN: function(int32, n) {
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var result = '';
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for (let i = 0; i < n; ++i) {
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result = digits[int32 & 0x3f] + result;
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int32 >>>= 6;
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}
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return result;
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},
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toInt: function(digitsStr) {
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var result = 0;
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var digits = digitsStr.split('');
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for (var i = 0; i < digits.length; i++) {
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result = (result << 6) + digitsMap[digits[i]];
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}
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return result;
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},
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};
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})();
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// Base64.fromInt(-2147483648); // gives "200000"
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// Base64.toInt("200000"); // gives -2147483648
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