javascript版归并排序mergeSort

javascript由于语言的一些特性，实现归并排序异常简单。详情看代码：

 
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<script type="text/javascript">
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Array.prototype.mergeSort=function(){
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    var merge=function(left,right){
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        var final=[];
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        while(left.length&&right.length){
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            final.push(left[0]<=right[0]?left.shift():right.shift());
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        }
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        return final.concat(left.concat(right));
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    };
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    var len=this.length;
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    if(len<2){
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        return this;
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    }
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    var mid=parseInt(len/2),
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        _left=this.slice(0,mid),
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        _right=this.slice(mid);
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    return merge(_left.mergeSort(),_right.mergeSort());
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}
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var arr=[];
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for(var i=0;i<50;i++){
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    arr.push(Math.floor(Math.random()*100));
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}
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document.write("original array is: "+arr+"<br/>");
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console.time("merge");
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document.write("sorted array is: "+arr.mergeSort());
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console.timeEnd("merge");
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</script>