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6 | "use strict";
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7 |
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8 |
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9 |
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10 |
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11 | class ArrayQueue {
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12 | |
13 |
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14 |
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15 | constructor(items) {
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16 |
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17 | this._list = items ? Array.from(items) : [];
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18 |
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19 | this._listReversed = [];
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20 | }
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21 |
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22 | |
23 |
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24 |
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25 |
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26 | get length() {
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27 | return this._list.length + this._listReversed.length;
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28 | }
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29 |
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30 | |
31 |
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32 |
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33 | clear() {
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34 | this._list.length = 0;
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35 | this._listReversed.length = 0;
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36 | }
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37 |
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38 | |
39 |
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40 |
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41 |
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42 |
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43 | enqueue(item) {
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44 | this._list.push(item);
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45 | }
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46 |
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47 | |
48 |
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49 |
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50 |
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51 | dequeue() {
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52 | if (this._listReversed.length === 0) {
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53 | if (this._list.length === 0) return undefined;
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54 | if (this._list.length === 1) return this._list.pop();
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55 | if (this._list.length < 16) return this._list.shift();
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56 | const temp = this._listReversed;
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57 | this._listReversed = this._list;
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58 | this._listReversed.reverse();
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59 | this._list = temp;
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60 | }
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61 | return this._listReversed.pop();
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62 | }
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63 |
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64 | |
65 |
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66 |
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67 |
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68 |
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69 | delete(item) {
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70 | const i = this._list.indexOf(item);
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71 | if (i >= 0) {
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72 | this._list.splice(i, 1);
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73 | } else {
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74 | const i = this._listReversed.indexOf(item);
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75 | if (i >= 0) this._listReversed.splice(i, 1);
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76 | }
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77 | }
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78 |
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79 | [Symbol.iterator]() {
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80 | let i = -1;
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81 | let reversed = false;
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82 | return {
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83 | next: () => {
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84 | if (!reversed) {
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85 | i++;
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86 | if (i < this._list.length) {
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87 | return {
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88 | done: false,
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89 | value: this._list[i]
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90 | };
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91 | }
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92 | reversed = true;
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93 | i = this._listReversed.length;
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94 | }
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95 | i--;
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96 | if (i < 0) {
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97 | return {
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98 | done: true,
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99 | value: undefined
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100 | };
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101 | }
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102 | return {
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103 | done: false,
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104 | value: this._listReversed[i]
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105 | };
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106 | }
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107 | };
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108 | }
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109 | }
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110 |
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111 | module.exports = ArrayQueue;
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