Assume the existence of a Widget class that implements the Comparable interface and thus has a compareTo method that accepts an Object parameter and returns an int.

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Assume the existence of a Widget class  that implements the Comparable interface and  thus has a compareTo method  that accepts an Object parameter and returns an int.

LANGUAGE: JAVA

CHALLENGE:

Assume the existence of a Widget class that implements the Comparable interface and
thus has a compareTo method that accepts an Object parameter and returns an int.

Write an efficient static method, getWidgetMatch, that has two parameters.
The first parameter is a reference to a Widget object. The second parameter
is a potentially very large array of Widget objects that has been sorted in
ascending order based on the Widget compareTo method. The getWidgetMatch searches
for an element in the array that matches the first parameter on the basis of the equals
method and returns true if found and false otherwise.

SOLUTION:

public static boolean getWidgetMatch(Widget a, Widget[] b){ 
    int lo=0; 
    int hi=b.length-1; 
    int m = 0; 
    int r; 
    while (lo<hi){ 
        m=(hi-lo); 
        r=a.compareTo(b[m]); 
        if (r==0) return true; 
        if (r>0) hi=m; 
        else lo=m; 
		   
        hi--;
    } 
    return a.equals(b[m]); 
} 


4 comments

  • KenM66 says:

    Not working. The return line is a bit off.

  • bjcarr160 says:

    More Hints:
    ⇒ You almost certainly should be using: +
    ⇒ You almost certainly should be using: /
    ⇒ You are using an incorrect number somewhere in your solution

    Want More Hints? Click here

    Problems Detected:
    ⇒ Incorrect result

  • shusma kafle says:

    public static boolean getWidgetMatch(Widget w, Widget [] widgets) {
    return getWidgetMatch(w, widgets, 0, widgets.length-1);
    }
    static boolean getWidgetMatch(Widget w, Widget [] widgets, int lo, int hi) {
    if (lo > hi) return false;
    int mid = (lo + hi) / 2;
    if (widgets[mid].compareTo(w) == 0)
    return true;
    else if (widgets[mid].compareTo(w) > 0)
    return getWidgetMatch(w, widgets, lo, mid-1);
    else
    return getWidgetMatch(w, widgets, mid+1, hi);
    }
    this works

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