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Using Javascipt---to realize the two-point lookup method _ basic knowledge

Source: Internet
Author: User
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Copy Code code as follows:

<meta http-equiv= "Content-type" content= "Text/html;charset=utf-8" >
<script type= "Text/javascript" >

Window.alert (Math.floor (5.7)); Take down the entire output 5

The binary lookup method array must be ordered

    function Binaryseach (arr,findval,leftindex,rightindex) {

        //Find the median value
        var midindex=math.floor (leftindex+ Rightindex)/2);
        var midval=arr[midindex];

       //Prevent infinite recursion
        if ( Leftindex>rightindex) {

           //description Cannot find
            Document.writeln ("not Found");
            return;
       }

To find
if (midval>findval) {

Look on the left.
Binaryseach (arr,findval,leftindex,midindex-1);
}else if (midval<findval) {

Description, look to the right.
Binaryseach (Arr,findval,midindex+1,rightindex);
}else{

Found the output or returned
Document.writeln ("Found, subscript as:" +midindex);
return;
}
}

var arr=[1,3,12,21,24,44,54,67];
Binaryseach (arr,67,0,arr.length-1);
</script>
<body></body>

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