前端js 算法收集
摘要：js模拟螺旋矩形算法 代码片段 1 <!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”> <html xmlns=……
js模拟螺旋矩形算法
代码片段 1
<!DOCTYPE html PUBLIC “-//W3C//DTD XHTML 1.0 Transitional//EN” “http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd”>
<html xmlns=”http://www.w3.org/1999/xhtml”>
<head>
<meta http-equiv=”content-type” content=”text/html;charset=utf-8″ />
<meta name=”generator” content=”editplus” />
<meta name=”author” content=”” />
<meta name=”keywords” content=”” />
<meta name=”description” content=”” />
<title> new document </title>
</head>
<body>
<div id=”container”></div>
<script type=”text/javascript”>
var cal = function (len) {
var helix = [[], [], [], [], [], []];
var min = 0;
var max = len – 1;
var row = 0;
var col = 0;
for (var i = 0; i < len * len; i++) {
helix[row][col] = i + 1;
if (row == min && col < max) {
col = col + 1;
}
else if (row < max && col == max) {
row = row + 1;
}
else if (row == max && col > min) {
col = col – 1;
}
else if (row > min && col == min) {
row = row – 1;
}
if (row – 1 == min && col == min) {
min = min + 1;
max = max – 1;
}
}
return helix;
};
var helix = cal(6);
var html = ”;
for (var i = 0; i < helix.length; i++) {
for (var j = 0; j < helix[i].length; j++) {
if (helix[i][j] < 10) {
helix[i][j] = “0” + helix[i][j];
}
html += helix[i][j] + ‘ ‘;
}
html += ”;
}
var container = document.getElementById(“container”);
container.innerHTML = html;
</script>
</body>
</html>
js最短路径代码片段 2
<html>
<head>
<title>use A* to find path…</title>
</head>
<body style=”margin:0px”>
<script>
/*
written by hjjboy
email:tianmashuangyi@163.com
qq:156809986
*/
var closelist = new Array(), openlist = new Array();
var gw = 10, gh = 10, gwh = 14;
var p_start = new Array(2), p_end = new Array(2);
var s_path, n_path = “”;
var num, bg, flag = 0;
var w = 30, h = 20;
function GetRound(pos) {
var a = new Array();
a[0] = (pos[0] + 1) + “,” + (pos[1] – 1);
a[1] = (pos[0] + 1) + “,” + pos[1];
a[2] = (pos[0] + 1) + “,” + (pos[1] + 1);
a[3] = pos[0] + “,” + (pos[1] + 1);
a[4] = (pos[0] – 1) + “,” + (pos[1] + 1);
a[5] = (pos[0] – 1) + “,” + pos[1];
a[6] = (pos[0] – 1) + “,” + (pos[1] – 1);
a[7] = pos[0] + “,” + (pos[1] – 1);
return a;
}
function GetF(arr) {
var t, G, H, F;
for (var i = 0; i < arr.length; i++) {
t = arr[i].split(“,”);
t[0] = parseInt(t[0]); t[1] = parseInt(t[1]);
if (IsOutScreen([t[0], t[1]]) || IsPass(arr[i]) || InClose([t[0], t[1]]) || IsStart([t[0], t[1]]) || !IsInTurn([t[0], t[1]]))
continue;
if ((t[0] – s_path[3][0]) * (t[1] – s_path[3][1]) != 0)
G = s_path[1] + gwh;
else
G = s_path[1] + gw;
if (InOpen([t[0], t[1]])) {
if (G < openlist[num][1]) {
openlist[num][0] = (G + openlist[num][2]);
openlist[num][1] = G;
openlist[num][4] = s_path[3];
}
else { G = openlist[num][1]; }
}
else {
H = (Math.abs(p_end[0] – t[0]) + Math.abs(p_end[1] – t[1])) * gw;
F = G + H;
arr[i] = new Array();
arr[i][0] = F; arr[i][1] = G; arr[i][2] = H; arr[i][3] = [t[0], t[1]]; arr[i][4] = s_path[3];
openlist[openlist.length] = arr[i];
}
if (maptt.rows[t[1]].cells[t[0]].style.backgroundColor != “#cccccc” && maptt.rows[t[1]].cells[t[0]].style.backgroundColor != “#0000ff” && maptt.rows[t[1]].cells[t[0]].style.backgroundColor != “#ff0000” && maptt.rows[t[1]].cells[t[0]].style.backgroundColor != “#00ff00”) {
maptt.rows[t[1]].cells[t[0]].style.backgroundColor = “#FF00FF”;
//maptt.rows[t[1]].cells[t[0]].innerHTML=”<font color=white>”+G+”</font>”;
}
}
}
function IsStart(arr) {
if (arr[0] == p_start[0] && arr[1] == p_start[1])
return true;
return false;
}
function IsInTurn(arr) {
if (arr[0] > s_path[3][0]) {
if (arr[1] > s_path[3][1]) {
if (IsPass((arr[0] – 1) + “,” + arr[1]) || IsPass(arr[0] + “,” + (arr[1] – 1)))
return false;
}
else if (arr[1] < s_path[3][1]) {
if (IsPass((arr[0] – 1) + “,” + arr[1]) || IsPass(arr[0] + “,” + (arr[1] + 1)))
return false;
}
}
else if (arr[0] < s_path[3][0]) {
if (arr[1] > s_path[3][1]) {
if (IsPass((arr[0] + 1) + “,” + arr[1]) || IsPass(arr[0] + “,” + (arr[1] – 1)))
return false;
}
else if (arr[1] < s_path[3][1]) {
if (IsPass((arr[0] + 1) + “,” + arr[1]) || IsPass(arr[0] + “,” + (arr[1] + 1)))
return false;
}
}
return true;
}
function IsOutScreen(arr) {
if (arr[0] < 0 || arr[1] < 0 || arr[0] > (w – 1) || arr[1] > (h – 1))
return true;
return false;
}
function InOpen(arr) {
var bool = false;
for (var i = 0; i < openlist.length; i++) {
if (arr[0] == openlist[i][3][0] && arr[1] == openlist[i][3][1]) {
bool = true; num = i; break;
}
}
return bool;
}
function InClose(arr) {
var bool = false;
for (var i = 0; i < closelist.length; i++) {
if ((arr[0] == closelist[i][3][0]) && (arr[1] == closelist[i][3][1])) {
bool = true; break;
}
}
return bool;
}
function IsPass(pos) {
if ((“;” + n_path + “;”).indexOf(“;” + pos + “;”) != -1)
return true;
return false;
}
function Sort(arr) {
var temp;
for (var i = 0; i < arr.length; i++) {
if (arr.length == 1) break;
if (arr[i][0] <= arr[i + 1][0]) {
temp = arr[i];
arr[i] = arr[i + 1];
arr[i + 1] = temp;
}
if ((i + 1) == (arr.length – 1))
break;
}
}
function main() {
GetF(GetRound(s_path[3]));
Sort(openlist);
s_path = openlist[openlist.length – 1];
closelist[closelist.length] = s_path;
openlist[openlist.length – 1] = null;
if (openlist.length == 0) { alert(“找不到路径”); return; }
openlist.length = openlist.length – 1;
if ((s_path[3][0] == p_end[0]) && (s_path[3][1] == p_end[1])) {
getPath();
}
else { maptt.rows[s_path[3][1]].cells[s_path[3][0]].style.backgroundColor = “#00ff00”; setTimeout(“main()”, 100); }
}
function getPath() {
var str = “”;
var t = closelist[closelist.length – 1][4];
while (1) {
str += t.join(“,”) + “;”;
maptt.rows[t[1]].cells[t[0]].style.backgroundColor = “#ffff00”;
for (var i = 0; i < closelist.length; i++) {
if (closelist[i][3][0] == t[0] && closelist[i][3][1] == t[1])
t = closelist[i][4];
}
if (t[0] == p_start[0] && t[1] == p_start[1])
break;
}
alert(str);
}
function setPos() {
var h = (Math.abs(p_end[0] – p_start[0]) + Math.abs(p_end[1] – p_start[1])) * gw;
s_path = [h, 0, h, p_start, p_start];
}
function set(id, arr) {
switch (id) {
case 1:
p_start = arr;
maptt.rows[arr[1]].cells[arr[0]].style.backgroundColor = “#ff0000”; break;
case 2:
p_end = arr; maptt.rows[arr[1]].cells[arr[0]].style.backgroundColor = “#0000ff”; break;
case 3:
n_path += arr.join(“,”) + “;”; maptt.rows[arr[1]].cells[arr[0]].style.backgroundColor = “#cccccc”; break;
default:
break;
}
}
function setflag(id) { flag = id; }
</script>
<table id=”maptt” cellspacing=”1″ cellpadding=”0″ border=”0″ bgcolor=”#000000″>
<script>
for (var i = 0; i < h; i++) {
document.write(“<tr>”);
for (var j = 0; j < w; j++) {
document.write(‘<td onclick=”set(flag,[‘ + j + ‘,’ + i + ‘]);” bgcolor=”#ffffff” width=”20″ height=”20″></td>’);
}
document.write(“</tr>”);
}
</script>
</table>
<a href=”javascript:setflag(1);”>设置起点</a><br>
<a href=’javascript:setflag(2);’>设置终点</a><br>
<a href=’javascript:setflag(3);’>设置障碍点</a><br>
<input type=”button” onclick=”setPos();main();this.disabled=true;” value=”find”>
</body>
</html>
js_常见排序算法代码片段 3
<html>
<head>
<script>
Array.prototype.swap = function (i, j) {
var temp = this[i];
this[i] = this[j];
this[j] = temp;
}
Array.prototype.bubbleSort = function () {
for (var i = this.length – 1; i > 0; –i) {
for (var j = 0; j < i; ++j) {
if (this[j] > this[j + 1]) this.swap(j, j + 1);
}
}
}
Array.prototype.selectionSort = function () {
for (var i = 0; i < this.length; ++i) {
var index = i;
for (var j = i + 1; j < this.length; ++j) {
if (this[j] < this[index]) index = j;
}
this.swap(i, index);
}
}
Array.prototype.insertionSort = function () {
for (var i = 1; i < this.length; ++i) {
var j = i, value = this[i];
while (j > 0 && this[j – 1] > value) {
this[j] = this[j – 1];
–j;
}
this[j] = value;
}
}
Array.prototype.shellSort = function () {
for (var step = this.length >> 1; step > 0; step >>= 1) {
for (var i = 0; i < step; ++i) {
for (var j = i + step; j < this.length; j += step) {
var k = j, value = this[j];
while (k >= step && this[k – step] > value) {
this[k] = this[k – step];
k -= step;
}
this[k] = value;
}
}
}
}
Array.prototype.quickSort = function (s, e) {
if (s == null) s = 0;
if (e == null) e = this.length – 1;
if (s >= e) return;
this.swap((s + e) >> 1, e);
var index = s – 1;
for (var i = s; i <= e; ++i) {
if (this[i] <= this[e]) this.swap(i, ++index);
}
this.quickSort(s, index – 1);
this.quickSort(index + 1, e);
}
Array.prototype.stackQuickSort = function () {
var stack = [0, this.length – 1];
while (stack.length > 0) {
var e = stack.pop(), s = stack.pop();
if (s >= e) continue;
this.swap((s + e) >> 1, e);
var index = s – 1;
for (var i = s; i <= e; ++i) {
if (this[i] <= this[e]) this.swap(i, ++index);
}
stack.push(s, index – 1, index + 1, e);
}
}
Array.prototype.mergeSort = function (s, e, b) {
if (s == null) s = 0;
if (e == null) e = this.length – 1;
if (b == null) b = new Array(this.length);
if (s >= e) return;
var m = (s + e) >> 1;
this.mergeSort(s, m, b);
this.mergeSort(m + 1, e, b);
for (var i = s, j = s, k = m + 1; i <= e; ++i) {
b[i] = this[(k > e || j <= m && this[j] < this[k]) ? j++ : k++];
}
for (var i = s; i <= e; ++i) this[i] = b[i];
}
Array.prototype.heapSort = function () {
for (var i = 1; i < this.length; ++i) {
for (var j = i, k = (j – 1) >> 1; k >= 0; j = k, k = (k – 1) >> 1) {
if (this[k] >= this[j]) break;
this.swap(j, k);
}
}
for (var i = this.length – 1; i > 0; –i) {
this.swap(0, i);
for (var j = 0, k = (j + 1) << 1; k <= i; j = k, k = (k + 1) << 1) {
if (k == i || this[k] < this[k – 1])–k;
if (this[k] <= this[j]) break;
this.swap(j, k);
}
}
}
function generate() {
var max = parseInt(txtMax.value), count = parseInt(txtCount.value);
if (isNaN(max) || isNaN(count)) {
alert(“个数和最大值必须是一个整数”);
return;
}
var array = [];
for (var i = 0; i < count; ++i) array.push(Math.round(Math.random() * max));
array.push(“９９”);
txtInput.value = array.join(” “);
txtOutput.value = “”;
}
function demo(type) {
var array = txtInput.value == “” ? [] : txtInput.value.replace().split(” “);
for (var i = 0; i < array.length; ++i) array[i] = parseInt(array[i]);
var t1 = new Date();
eval(“array.” + type + “Sort()”);
var t2 = new Date();
lblTime.innerText = t2.valueOf() – t1.valueOf();
txtOutput.value = array.join(” “);
}
function search() {
var txtSearch = document.getElementById(“txtSearch”);
var array = txtInput.value == “” ? [] : txtInput.value.replace().split(” “);
var arrayResult = new Array();
var t1 = new Date();
alert(array.length);
for (var i = 0; i < array.length; ++i) {
if (array[i].indexOf(txtSearch.value) >= 0) {
arrayResult.push(array[i]);
}
}
//eval(“array.” + type + “Sort()”);
var t2 = new Date();
lblTime.innerText = t2.valueOf() – t1.valueOf();
txtOutput.value = arrayResult.join(” “);
}
</script>
</head>
<body onload=generate()>
<table style=”width:100%;height:100%;font-size:12px;font-family:宋体”>
<tr>
<td align=right>
<textarea id=txtInput readonly style=”width:100px;height:100%”></textarea>
</td>
<td width=150 align=center>
检索 <input id=”txtSearch” value=”” style=”width:50px”><br><br>
随机数个数<input id=txtCount value=500 style=”width:50px”><br><br>
最大随机数<input id=txtMax value=1000 style=”width:50px”><br><br>
<button onclick=generate()>重新生成</button><br><br><br><br>
耗时(毫秒)：<label id=lblTime></label><br><br><br><br>
<button onclick=demo(“bubble”)>冒泡排序</button><br><br>
<button onclick=demo(“selection”)>选择排序</button><br><br>
<button onclick=demo(“insertion”)>插入排序</button><br><br>
<button onclick=demo(“shell”)>谢尔排序</button><br><br>
<button onclick=demo(“quick”)>快速排序(递归)</button><br><br>
<button onclick=demo(“stackQuick”)>快速排序(堆栈)</button><br><br>
<button onclick=demo(“merge”)>归并排序</button><br><br>
<button onclick=demo(“heap”)>堆排序</button><br><br>
<button onclick=search()>检索</button><br><br>
</td>
<td align=left>
<textarea id=txtOutput readonly style=”width:100px;height:100%”></textarea>
</td>
</tr>
</table>
</body>
</html>
这是网上的例子，感觉好头疼啊，有没有算法教程，我看那书里面都没有讲解的啊！
--------------------------------------------------------------------------------------
[图像混合（溶图）算法的javascript实现](http://www.html-js.com/article/1801)
[各种数据结构与算法知识入门经典](http://www.html-js.com/blog/2316)
数据结构与算法JavaScript描述 [试读](http://images.china-pub.com/ebook3800001-3805000/3804002/ch01.pdf)
[常用算法](http://book.51cto.com/art/201311/415262.htm)
iphone前端开发是什么 web前端开发是什么语言 web前端开发要什么软件 » 本文来自：前端开发者 » 《前端js 算法收集》
» 本文链接地址：https://www.rokub.com/5610.html
» 您也可以订阅本站：https://www.rokub.com
近期评论