119 lines
2.3 KiB
Markdown
119 lines
2.3 KiB
Markdown
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---
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id: 56533eb9ac21ba0edf2244c6
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title: 排隊
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/ca8Q8tP'
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forumTopicId: 18307
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dashedName: stand-in-line
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---
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# --description--
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在計算機科學中隊列（<dfn>queue</dfn>）是一個抽象的數據結構（<dfn>Data Structure</dfn>），隊列中的條目都是有秩序的。 新的條目會被加到隊列的末尾，舊的條目會從隊列的頭部被移出。
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寫一個函數 `nextInLine`，用一個數組（`arr`）和一個數字（`item`）作爲參數。
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把數字添加到數組的結尾，然後移出數組的第一個元素。
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最後 `nextInLine` 函數應該返回被刪除的元素。
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# --hints--
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`nextInLine([], 5)` 應該返回一個數字。
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```js
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assert.isNumber(nextInLine([], 5));
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```
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`nextInLine([], 1)` 應該返回 `1`
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```js
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assert(nextInLine([], 1) === 1);
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```
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`nextInLine([2], 1)` 應該返回 `2`
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```js
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assert(nextInLine([2], 1) === 2);
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```
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`nextInLine([5,6,7,8,9], 1)` 應該返回 `5`
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```js
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assert(nextInLine([5, 6, 7, 8, 9], 1) === 5);
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```
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在 `nextInLine(testArr, 10)` 執行後 `testArr[4]` 應該是 `10`
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```js
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nextInLine(testArr, 10);
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assert(testArr[4] === 10);
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```
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# --seed--
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## --before-user-code--
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```js
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var logOutput = [];
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var originalConsole = console
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function capture() {
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var nativeLog = console.log;
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console.log = function (message) {
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logOutput.push(message);
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if(nativeLog.apply) {
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nativeLog.apply(originalConsole, arguments);
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} else {
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var nativeMsg = Array.prototype.slice.apply(arguments).join(' ');
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nativeLog(nativeMsg);
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}
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};
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}
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function uncapture() {
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console.log = originalConsole.log;
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}
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capture();
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```
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## --after-user-code--
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```js
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uncapture();
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testArr = [1,2,3,4,5];
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(function() { return logOutput.join("\n");})();
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```
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## --seed-contents--
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```js
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function nextInLine(arr, item) {
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// Only change code below this line
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return item;
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// Only change code above this line
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}
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// Setup
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var testArr = [1,2,3,4,5];
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// Display code
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console.log("Before: " + JSON.stringify(testArr));
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console.log(nextInLine(testArr, 6));
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console.log("After: " + JSON.stringify(testArr));
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```
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# --solutions--
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```js
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var testArr = [ 1,2,3,4,5];
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function nextInLine(arr, item) {
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arr.push(item);
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return arr.shift();
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}
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```
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