feat: add sorting algorithms in javascript (doocs#358)

* add bubble sort in javascript

* add insertion sort in javascript

* add selection sort in javascript

* add merge sort in javascript

* add quick sort in javascript

* reformat code

* modify bubblesort

* reformat code

Author: lo0b0o

basic/sorting/BubbleSort/BubbleSort.js

@@ -0,0 +1,20 @@
+function bubbleSort(inputArr) {
+    let len = inputArr.length;
+    let swapped = false;
+    for (let i = 1; i <= len - 1; i++) {
+        swapped = false;
+        for (let j = 0; j < len - 1; j++) {
+            if (inputArr[j] > inputArr[j + 1]) {
+                let temp = inputArr[j];
+                inputArr[j] = inputArr[j + 1];
+                inputArr[j + 1] = temp;
+                swapped = true
+            }
+        }
+        if (swapped === false) break;
+    }
+    return (inputArr)
+}
+
+let arr = [6, 3, 2, 1, 5];
+console.log(bubbleSort(arr))

basic/sorting/BubbleSort/README.md

@@ -41,6 +41,30 @@ public class BubbleSort {
     }
 }
 ```
+### **JavaScript**
+
+```javascript
+function bubbleSort(inputArr) {
+    let len = inputArr.length;
+    let swapped = false;
+    for (let i = 1; i <= len - 1; i++) {
+        swapped = false;
+        for (let j = 0; j < len - 1; j++) {
+            if (inputArr[j] > inputArr[j + 1]) {
+                let temp = inputArr[j];
+                inputArr[j] = inputArr[j + 1];
+                inputArr[j + 1] = temp;
+                swapped = true
+            }
+        }
+        if (swapped === false) break;
+    }
+    return (inputArr)
+}
+
+let arr = [6, 3, 2, 1, 5];
+console.log(bubbleSort(arr))
+```
 
 <!-- tabs:end -->
 

basic/sorting/InsertionSort/InsertionSort.js

@@ -0,0 +1,16 @@
+function insertionSort(inputArr) {
+    let len = inputArr.length;
+    for (let i = 1; i <= len - 1; i++) {
+        let temp = inputArr[i];
+        let j = i - 1;
+        while (j >= 0 && inputArr[j] > temp) {
+            inputArr[j + 1] = inputArr[j];
+            j--;
+        }
+        inputArr[j + 1] = temp;
+    }
+    return (inputArr);
+}
+
+let arr = [6, 3, 2, 1, 5];
+console.log(insertionSort(arr))

basic/sorting/InsertionSort/README.md

@@ -41,6 +41,25 @@ public class InsertionSort {
     }
 }
 ```
+### **JavaScript**
+```javascript
+function insertionSort(inputArr) {
+    let len = inputArr.length;
+    for (let i = 1; i <= len - 1; i++) {
+        let temp = inputArr[i];
+        let j = i - 1;
+        while (j >= 0 && inputArr[j] > temp) {
+            inputArr[j + 1] = inputArr[j];
+            j--;
+        }
+        inputArr[j + 1] = temp;
+    }
+    return (inputArr);
+}
+
+let arr = [6, 3, 2, 1, 5];
+console.log(insertionSort(arr))
+```
 
 <!-- tabs:end -->
 

basic/sorting/MergeSort/MergeSort.js

@@ -0,0 +1,23 @@
+function mergeSort(arr) {
+    if (arr.length < 2) return arr;
+    let mid = Math.ceil(arr.length / 2);
+    let arrLeft = mergeSort(arr.splice(0, mid));
+    let arrRight = mergeSort(arr.splice(-mid));
+    return merge(arrLeft, arrRight);
+}
+
+function merge(arr1, arr2) {
+    let arr = [];
+    while (arr1.length && arr2.length) {
+        if (arr1[0] < arr2[0]) {
+            arr.push(arr1.shift());
+        } else {
+            arr.push(arr2.shift());
+        }
+    }
+    return [...arr, ...arr1, ...arr2];
+
+}
+
+arr = [3, 5, 6, 2, 1, 7, 4];
+console.log(mergeSort(arr));

basic/sorting/MergeSort/README.md

@@ -56,6 +56,35 @@ public class MergeSort {
 }
 ```
 
+### **JavaScript**
+
+```JavaScript
+function mergeSort(arr) {
+    if (arr.length < 2) return arr;
+    let mid = Math.ceil(arr.length / 2);
+    let arrLeft = mergeSort(arr.splice(0, mid));
+    let arrRight = mergeSort(arr.splice(-mid));
+    return merge(arrLeft, arrRight);
+}
+
+function merge(arr1, arr2) {
+    let arr = [];
+    while (arr1.length && arr2.length) {
+        if (arr1[0] < arr2[0]) {
+            arr.push(arr1.shift());
+        } else {
+            arr.push(arr2.shift());
+        }
+    }
+    return [...arr, ...arr1, ...arr2];
+
+}
+
+arr = [3, 5, 6, 2, 1, 7, 4];
+console.log(mergeSort(arr));
+```
+
+
 <!-- tabs:end -->
 
 ## 算法分析

basic/sorting/QuickSort/QuickSort.js

@@ -0,0 +1,33 @@
+function quickSort(arr) {
+    let len = arr.length;
+    return qSort(arr, 0, len - 1);
+}
+
+function qSort(arr, left, right) {
+    if (left < right) {
+        let index = partition(arr, left, right);
+        qSort(arr, left, index - 1);
+        qSort(arr, index + 1, right);
+    }
+    return arr;
+}
+
+function partition(arr, left, right) {
+    let temp = arr[left];
+    while (left < right) {
+        while (left < right && arr[right] > temp) {
+            right--;
+        }
+        arr[left] = arr[right];
+        while (left < right && arr[left] <= temp) {
+            left++;
+        }
+        arr[right] = arr[left];
+    }
+    arr[left] = temp;
+    console.log(arr)
+    return left;
+}
+
+arr = [3, 5, 6, 2, 1, 7, 4];
+console.log(quickSort(arr))

basic/sorting/QuickSort/README.md

@@ -53,6 +53,44 @@ public class QuickSort {
         System.out.println(Arrays.toString(nums));
     }
 }
+```
+### **JavaScript**
+
+```javascript
+function quickSort(arr) {
+    let len = arr.length;
+    return qSort(arr, 0, len - 1);
+}
+
+function qSort(arr, left, right) {
+    if (left < right) {
+        let index = partition(arr, left, right);
+        qSort(arr, left, index - 1);
+        qSort(arr, index + 1, right);
+    }
+    return arr;
+}
+
+function partition(arr, left, right) {
+    let temp = arr[left];
+    while (left < right) {
+        while (left < right && arr[right] > temp) {
+            right--;
+        }
+        arr[left] = arr[right];
+        while (left < right && arr[left] <= temp) {
+            left++;
+        }
+        arr[right] = arr[left];
+    }
+    arr[left] = temp;
+    console.log(arr)
+    return left;
+}
+
+arr = [3, 5, 6, 2, 1, 7, 4];
+console.log(quickSort(arr))
+
 ```
 
 <!-- tabs:end -->

basic/sorting/SelectionSort/README.md

@@ -40,6 +40,30 @@ public class SelectionSort {
 
 ```
 
+### **JavaScript**
+
+```javascript
+function selectionSort(inputArr) {
+    let len = inputArr.length;
+    for (let i = 0; i <= len - 2; i++) {
+        let j = i;
+        let min = j;
+        while (j <= len - 1) {
+            if (inputArr[j] < inputArr[min])
+                min = j;
+            j++;
+        }
+        let temp = inputArr[i];
+        inputArr[i] = inputArr[min];
+        inputArr[min] = temp;
+    }
+    return inputArr;
+}
+
+let arr = [6, 3, 2, 1, 5];
+console.log(selectionSort(arr))
+```
+
 <!-- tabs:end -->
 
 ## 算法分析

basic/sorting/SelectionSort/SelectionSort.js

@@ -0,0 +1,19 @@
+function selectionSort(inputArr) {
+    let len = inputArr.length;
+    for (let i = 0; i <= len - 2; i++) {
+        let j = i;
+        let min = j;
+        while (j <= len - 1) {
+            if (inputArr[j] < inputArr[min])
+                min = j;
+            j++;
+        }
+        let temp = inputArr[i];
+        inputArr[i] = inputArr[min];
+        inputArr[min] = temp;
+    }
+    return inputArr;
+}
+
+let arr = [6, 3, 2, 1, 5];
+console.log(selectionSort(arr))