27 lines
687 B
JavaScript
27 lines
687 B
JavaScript
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export class Queue {
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#pushStack;
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#shiftStack;
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constructor() {
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this.#pushStack = [];
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this.#shiftStack = [];
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}
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get length() {
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return this.#pushStack.length + this.#shiftStack.length;
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}
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push(elem) {
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this.#pushStack.push(elem);
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}
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shift() {
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if (this.#shiftStack.length === 0 && this.#pushStack.length > 0) {
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this.#shiftStack = this.#pushStack.reverse();
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this.#pushStack = [];
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}
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return this.#shiftStack.pop();
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}
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first() {
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return this.#shiftStack.length !== 0
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? this.#shiftStack[this.#shiftStack.length - 1]
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: this.#pushStack[0];
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}
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}
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