几种经典排序算法的JS实现

一.冒泡排序

 function BubbleSort(array) {
var length = array.length;
for (var i = length - 1; i > 0; i--) { //用于缩小范围
for (var j = 0; j < i; j++) { //在范围内进行冒泡,在此范围内最大的一个将冒到最后面
if (array[j] > array[j+1]) {
var temp = array[j];
array[j] = array[j+1];
array[j+1] = temp;
}
}
console.log(array);
console.log("-----------------------------");
}
return array;
} var arr = [10,9,8,7,7,6,5,11,3];
var result = BubbleSort(arr);
console.log(result);
/*
[ 9, 8, 7, 7, 6, 5, 10, 3, 11 ]
-----------------------------
[ 8, 7, 7, 6, 5, 9, 3, 10, 11 ]
-----------------------------
[ 7, 7, 6, 5, 8, 3, 9, 10, 11 ]
-----------------------------
[ 7, 6, 5, 7, 3, 8, 9, 10, 11 ]
-----------------------------
[ 6, 5, 7, 3, 7, 8, 9, 10, 11 ]
-----------------------------
[ 5, 6, 3, 7, 7, 8, 9, 10, 11 ]
-----------------------------
[ 5, 3, 6, 7, 7, 8, 9, 10, 11 ]
-----------------------------
[ 3, 5, 6, 7, 7, 8, 9, 10, 11 ]
-----------------------------
[ 3, 5, 6, 7, 7, 8, 9, 10, 11 ]
*/

二.选择排序

 function SelectionSort(array) {
var length = array.length;
for (var i = 0; i < length; i++) { //缩小选择的范围
var min = array[i]; //假定范围内第一个为最小值
var index = i; //记录最小值的下标
for (var j = i + 1; j < length; j++) { //在范围内选取最小值
if (array[j] < min) {
min = array[j];
index = j;
}
}
if (index != i) { //把范围内最小值交换到范围内第一个
var temp = array[i];
array[i] = array[index];
array[index] = temp;
}
console.log(array);
console.log("---------------------");
}
return array;
} var arr = [ 1, 10, 100, 90, 65, 5, 4, 10, 2, 4 ];
var result = SelectionSort(arr);
console.log(result);
/*
[ 1, 10, 100, 90, 65, 5, 4, 10, 2, 4 ]
---------------------
[ 1, 2, 100, 90, 65, 5, 4, 10, 10, 4 ]
---------------------
[ 1, 2, 4, 90, 65, 5, 100, 10, 10, 4 ]
---------------------
[ 1, 2, 4, 4, 65, 5, 100, 10, 10, 90 ]
---------------------
[ 1, 2, 4, 4, 5, 65, 100, 10, 10, 90 ]
---------------------
[ 1, 2, 4, 4, 5, 10, 100, 65, 10, 90 ]
---------------------
[ 1, 2, 4, 4, 5, 10, 10, 65, 100, 90 ]
---------------------
[ 1, 2, 4, 4, 5, 10, 10, 65, 100, 90 ]
---------------------
[ 1, 2, 4, 4, 5, 10, 10, 65, 90, 100 ]
---------------------
[ 1, 2, 4, 4, 5, 10, 10, 65, 90, 100 ]
---------------------
[ 1, 2, 4, 4, 5, 10, 10, 65, 90, 100 ]
*/

三.插入排序

 function InsertionSort(array) {
var length = array.length;
for (var i = 0; i < length - 1; i++) {
//i代表已经排序好的序列最后一项下标
var insert = array[i+1];
var index = i + 1;//记录要被插入的下标
for (var j = i; j >= 0; j--) {
if (insert < array[j]) {
//要插入的项比它小,往后移动
array[j+1] = array[j];
index = j;
}
}
array[index] = insert;
console.log(array);
console.log("-----------------------");
}
return array;
} var arr = [100,90,80,62,80,8,1,2,39];
var result = InsertionSort(arr);
console.log(result);
/*
[ 90, 100, 80, 62, 80, 8, 1, 2, 39 ]
-----------------------
[ 80, 90, 100, 62, 80, 8, 1, 2, 39 ]
-----------------------
[ 62, 80, 90, 100, 80, 8, 1, 2, 39 ]
-----------------------
[ 62, 80, 80, 90, 100, 8, 1, 2, 39 ]
-----------------------
[ 8, 62, 80, 80, 90, 100, 1, 2, 39 ]
-----------------------
[ 1, 8, 62, 80, 80, 90, 100, 2, 39 ]
-----------------------
[ 1, 2, 8, 62, 80, 80, 90, 100, 39 ]
-----------------------
[ 1, 2, 8, 39, 62, 80, 80, 90, 100 ]
-----------------------
[ 1, 2, 8, 39, 62, 80, 80, 90, 100 ]
*/

四.希尔排序

 function ShellSort(array) {
var length = array.length;
var gap = Math.round(length / 2);
while (gap > 0) {
for (var i = gap; i < length; i++) {
var insert = array[i];
var index = i;
for (var j = i; j >= 0; j-=gap) {
if (insert < array[j]) {
array[j+gap] = array[j];
index = j;
}
}
array[index] = insert;
}
console.log(array);
console.log("-----------------------");
gap = Math.round(gap/2 - 0.1);
}
return array;
} var arr = [ 13, 14, 94, 33, 82, 25, 59, 94, 65, 23, 45, 27, 73, 25, 39, 10 ];
var result = ShellSort(arr);
console.log(result);
/*
[ 13, 14, 45, 27, 73, 25, 39, 10, 65, 23, 94, 33, 82, 25, 59, 94 ]
-----------------------
[ 13, 14, 39, 10, 65, 23, 45, 27, 73, 25, 59, 33, 82, 25, 94, 94 ]
-----------------------
[ 13, 10, 39, 14, 45, 23, 59, 25, 65, 25, 73, 27, 82, 33, 94, 94 ]
-----------------------
[ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ]
-----------------------
[ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ]
*/

五.归并排序

 function MergeSort(array) {
var length = array.length;
if (length <= 1) {
return array;
} else {
var num = Math.ceil(length/2);
var left = MergeSort(array.slice(0, num));
var right = MergeSort(array.slice(num, length));
return merge(left, right);
}
} function merge(left, right) {
console.log(left);
console.log(right);
var a = new Array();
while (left.length > 0 && right.length > 0) {
if (left[0] <= right[0]) {
var temp = left.shift();
a.push(temp);
} else {
var temp = right.shift();
a.push(temp);
}
}
if (left.length > 0) {
a = a.concat(left);
}
if (right.length > 0) {
a = a.concat(right);
}
console.log(a);
console.log("-----------------------------");
return a;
} var arr = [ 13, 14, 94, 33, 82, 25, 59, 94, 65, 23, 45, 27, 73, 25, 39, 10 ];
var result = MergeSort(arr);
console.log(result);
/*
[ 13 ]
[ 14 ]
[ 13, 14 ]
-----------------------------
[ 94 ]
[ 33 ]
[ 33, 94 ]
-----------------------------
[ 13, 14 ]
[ 33, 94 ]
[ 13, 14, 33, 94 ]
-----------------------------
[ 82 ]
[ 25 ]
[ 25, 82 ]
-----------------------------
[ 59 ]
[ 94 ]
[ 59, 94 ]
-----------------------------
[ 25, 82 ]
[ 59, 94 ]
[ 25, 59, 82, 94 ]
-----------------------------
[ 13, 14, 33, 94 ]
[ 25, 59, 82, 94 ]
[ 13, 14, 25, 33, 59, 82, 94, 94 ]
-----------------------------
[ 65 ]
[ 23 ]
[ 23, 65 ]
-----------------------------
[ 45 ]
[ 27 ]
[ 27, 45 ]
-----------------------------
[ 23, 65 ]
[ 27, 45 ]
[ 23, 27, 45, 65 ]
-----------------------------
[ 73 ]
[ 25 ]
[ 25, 73 ]
-----------------------------
[ 39 ]
[ 10 ]
[ 10, 39 ]
-----------------------------
[ 25, 73 ]
[ 10, 39 ]
[ 10, 25, 39, 73 ]
-----------------------------
[ 23, 27, 45, 65 ]
[ 10, 25, 39, 73 ]
[ 10, 23, 25, 27, 39, 45, 65, 73 ]
-----------------------------
[ 13, 14, 25, 33, 59, 82, 94, 94 ]
[ 10, 23, 25, 27, 39, 45, 65, 73 ]
[ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ]
-----------------------------
[ 10, 13, 14, 23, 25, 25, 27, 33, 39, 45, 59, 65, 73, 82, 94, 94 ]
*/

六.快速排序

 function QuickSort(array) {
var length = array.length;
if (length <= 1) {
return array;
} else {
var smaller = [];
var bigger = [];
var base = [array[0]];
for (var i = 1; i < length; i++) {
if (array[i] <= base[0]) {
smaller.push(array[i]);
} else {
bigger.push(array[i]);
}
}
console.log(smaller.concat(base.concat(bigger)));
console.log("-----------------------");
return QuickSort(smaller).concat(base.concat(QuickSort(bigger)));
}
} var arr = [ 8, 10, 100, 90, 65, 5, 4, 10, 2, 4 ];
var result = QuickSort(arr);
console.log(result);
/*
[ 5, 4, 2, 4, 8, 10, 100, 90, 65, 10 ]
-----------------------
[ 4, 2, 4, 5 ]
-----------------------
[ 2, 4, 4 ]
-----------------------
[ 2, 4 ]
-----------------------
[ 10, 10, 100, 90, 65 ]
-----------------------
[ 90, 65, 100 ]
-----------------------
[ 65, 90 ]
-----------------------
[ 2, 4, 4, 5, 8, 10, 10, 65, 90, 100 ]
*/

七.堆排序

 function HeapSort(array) {
function swap(i,j) {
var temp = array[i];
array[i] = array[j];
array[j] = temp;
} function MaxHeap(start, end) {
var dad = start;
var son = dad * 2 + 1;//子节点中的左节点
if (son >= end)
return;
if (son + 1 < end && array[son] < array[son + 1])//比较左右节点的值,选择大的那个
son++;
if (array[dad] <= array[son]) {//如果父节点小于子节点时,交换父子内容再继续子节点和孙节点比较
swap(dad, son);
MaxHeap(son, end);
}
} var len = array.length;
//从最后一个父节点开始创建最大堆
for (var i = Math.floor(len / 2) - 1; i >= 0; i--) {
console.log(array);
MaxHeap(i,len);
console.log(array);
console.log("----------------------------------");
}
//将最大的交换到最后一个位置;在调整最大堆,直至调整到第一个
for (var i = len - 1; i > 0; i--) {
swap(0,i);
MaxHeap(0,i);
console.log(array);
console.log("----------------------------");
}
return array;
} var a = [1,2,3,4,5];
HeapSort(a);
/*
[ 1, 2, 3, 4, 5 ]
[ 1, 5, 3, 4, 2 ]
----------------------------------
[ 1, 5, 3, 4, 2 ]
[ 5, 4, 3, 1, 2 ]
----------------------------------
[ 4, 2, 3, 1, 5 ]
----------------------------
[ 3, 2, 1, 4, 5 ]
----------------------------
[ 2, 1, 3, 4, 5 ]
----------------------------
[ 1, 2, 3, 4, 5 ]
----------------------------
*/

参考资料:

http://wuchong.me/blog/2014/02/09/algorithm-sort-summary/

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