显示所有非重复组合

-4

创建一个HTML页面，该页面接受用户在文本字段中输入的长度为3个数字的非重复整数。当用户按下“Display”按钮时，JavaScript中创建的函数应该能够显示全部6个非重复组合。显示所有非重复组合

例

输入Integer

"123"

函数应该返回：

"123, 132, 213, 231, 312, 321"

来源

2012-09-19 kidd

[你到目前为止尝试过什么？]（http://whathaveyoutried.com） – Pointy

你卡在哪里？你有什么问题？ – Msonic

这个例子接受最多12个数字或字母，但我敢打赌，你可以把它适应只允许3位数字：

<!doctype html> 
<html lang="en"> 
<head> 
<meta charset= "utf-8"> 
<title>Small Combinations</title> 

<style> 
form{font-size:1.25em} 
fieldset{border:none} 
input, button, label, textarea,legend{font-size:inherit; } 
input, label{text-align:right; margin:0 1ex; 
background-color:white;color:black;} 
button{cursor:pointer} 
button:hover, button:focus{color:red} 
</style> 

<script> 
Math.factorial= function(n){ 
    var i= n; 
    while(--i) n*= i; 
    return n; 
} 

//An object containing members and properties of the premutations of a set 
function Combos(str){ 
    if(!(this instanceof Combos)){ 
     return new Combos(str); 
    } 
    str= str.replace(/\W+/g, '').toLowerCase(); 
    var show, deep, def, cf= Combos.diffcoeff(str); 
    show= deep= Math.min(cf,5040); 
    def={ 
     coeff: cf, count: 0, 
     limit: deep, next: [], 
     seed: str.split('').sort().join(''), 
     showlimit: show, text: str, items: {} 
    } 
    for(var p in def) this[p]= def[p]; 
} 
// methods to collect the members 
var MP={ 
    collect: function(s){ 
     var items= this.items, next= this.next, i, ch= s.split(''); 
     for(i= 0; i < ch.length; i++){ 
      next.push(ch.splice(i, 1)); 
      if(ch.length== 0) items[next.join('')]= 1; 
      this.collect(ch.join('')); 
      ch.splice(i, 0, next.pop()); 
     } 
    }, 
    counter: function(){ 
     var W= this.items, c= 0; 
     for(var p in W){ 
      if(W.hasOwnProperty(p))++c; 
     } 
     return c; 
    }, 
    //uses timeout to break up long calculation 
    getSome: function(){ 
     if(Combos.quit){ 
      return Combos.display(this); 
     } 
     var T= this, items= T.items, n= T.count, max= T.limit, 
     ch= this.seed.split(''), next, tick= 2000; 
     while(--tick> 0 && n< max){ 
      next= ch.sort(function(){ 
       return .5-Math.random() 
      }).join(''); 
      if(!items[next]) items[next]= ++n; 
     }  
     T.count= n; 
     if(n< max){ 
      Combos.where.value= n; 
      Combos.timer= setTimeout(function(){ 
       T.getSome() 
      }, 
      0); 
     } 
     else{ 
      Combos.timer= setTimeout(function(){ 
       Combos.display(T) 
      }, 
      0); 
     } 
    } 
} 
for(var p in MP)Combos.prototype[p]=MP[p]; 

//static methods of Combos 
var M1={ 
    //calculate # of permutations 
    diffcoeff: function(str){ 
     var items= {},next, 
     members= String(str).split('').sort(), L=members.length; 
     for(var i=0;i<L;i++){ 
      tem=members[i]; 
      if(!items[tem]) items[tem]= 1; 
      else ++items[tem]; 
     } 
     var n= Math.factorial(str.length), g= items; 
     for(var p in g){ 
      if(g.hasOwnProperty(p) && g[p]> 1){ 
       n/= Math.factorial(g[p]); 
      } 
     } 
     return n; 
    }, 
    // block until complete, set timer to call display 
    demo: function(str){ 
     if(Combos.startTime) return; 
     var T= Combos(str); 
     Combos.where.value+= '\n'; 
     Combos.where.ondblclick= function(){ 
      Combos.quit= true; 
     } 
     Combos.startTime= +(new Date); 
     //limit the number shown- (arbitrary and optional) 
     if(str.length> 7) T.getSome() 
     else{ 
      T.collect(T.seed); 
      setTimeout(function(){ 
       T.count= T.counter(); 
       Combos.display(T); 
      }, 
      0); 
     } 
    }, 
    // show results of calculations 
    display: function(A){ 
     var W= [], L, tc= A.count, tm= +(new Date), 
     items= A.items, report= '', 
     str= A.text, coeff= A.coeff, 
     limit= A.showlimit; 

     var tm= ((tm-Combos.startTime)/1000).toFixed(3)+' sec'; 
     if(limit){ 
      for(var p in items){ 
       if(items.hasOwnProperty(p)) W.push(p); 
       if(W.length=== limit) break; 
      } 
     } 
     L= W.length; 
     report= str+': '+coeff+' anagrams '; 
     if(coeff>= L){ 
      if(coeff=== tc) report+= ' found '; 
      report+= '('+L +' shown)'; 
      if(coeff> tc) report+= ' found '+tc; 
     } 
     report+= ' in '+tm+'\n\n'+W.sort().join(', ')+'\n'; 
     Combos.where.value= report; 
     delete Combos.startTime; 
     delete Combos.quit; 
     Combos.where.ondblclick= ''; 
     A.elapsed= tm; 
     var ins=document.getElementsByTagName('input'); 
     ins[0].disabled= false; 
     ins[0].focus(); 
     ins[0].select(); 
    }, 
    where: '' 
} 
for(var p in M1)Combos[p]=M1[p]; 

// page demo, set up event handlers 
window.onload= function(){ 
    var cf, str, show, 
    F= document.forms[0], 
    ins= F.getElementsByTagName('input'), 
    btn=F.getElementsByTagName('button')[0], 
    btn2=F.getElementsByTagName('button')[1], 

    sp=document.getElementById('showcoeff'); 
    //run on enter 
    F.onsubmit=function(){ 
     btn.onclick(); 
     return false;// don't actually submit anything 
    } 
    Combos.where= F.getElementsByTagName('textarea')[0]; 
    //run on click 
    btn.onclick= function(){ 
     if(Combos.startTime) return; 
     str= ins[0].value.replace(/\W+/g, '').toLowerCase(); 
     if(str){ 
      sp.firstChild.data=Combos.diffcoeff(str); 
      ins[0].value=str; 
      Combos.demo(str); 
     } 
    } 
} 
</script> 
</head> 
<body> 
<h1>Combinations and Permutations- 1</h1> 
<form> 
<fieldset> 
<legend>Rearranging groups of elements</legend> 
<p > 
<label>Enter a word or sequence of digits: 
<input size="12" maxLength="12" value="123"> 
</label><button type="submit">Compute</button> 
</p> 
<p> 
</fieldset> 
<h3>Unique permutations: <span id="showcoeff">&nbsp;</span></h3> 
<textarea cols="80" rows="20" readonly></textarea> 
</p> 
</form> 
</body> 
</html>

来源

2012-09-19 18:19:37 kennebec

这里是一个非常简单的版本：http://jsfiddle.net/uXFdZ/

<script type="text/javascript"> 

    var result = ""; 

    function perm(s) 
    { 
     result = ""; 
     permAux(s, 0); 
    } 

    function permAux(s, currentPos) 
    { 
     if (currentPos == s.length-1) //If the index is at the end, it's a unique permutation 
      result += (s + "\n"); 
     else 
      for(var k = 0; k < s.length-currentPos; k++) //shifts the characters around k times, each time permutating the substring after the currentPos 
       permAux(circularShift(s, currentPos, k), currentPos+1); 
    } 

    function circularShift(s, startPos, shiftTimes) 
    { 
     if (shiftTimes >= s.length) 
      shiftTimes %= s.length; 

     //first substring takes the substring that will not be shifted, second and third exchange the shifted areas 
     return (s.substr(0, startPos) + s.substr(s.length-shiftTimes, shiftTimes) + s.substr(startPos, s.length-shiftTimes-startPos)); 
    } 

    function showResults() { 

     var sValue = document.getElementById("number").value; 

     var iValue = parseInt(sValue); 

     if (isNaN(iValue)) { 
      alert("Please enter a number."); 
      return; 
     } 

     perm(sValue); 

     alert(result); 

} 

</script> 

<input title="Please Enter a number" id="number" name="number" maxlength="3" /> 
<button onclick="showResults()">Go</button>

置换代码从here调整。

来源

2012-09-19 18:30:32

显示所有非重复组合

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