Question

I wrote the following code for solving a problem but it doesn’t work. The link to the question is here.

  public boolean linearIn(int[] outer, int[] inner) {

    boolean result = false;

        if(inner.length == 0)
            return true;

        index: for(int x: inner) {
                    for(int y: outer) {
                        if(x==y) {
                            result = true;
                            break;
                        }
                        else {
                            result = false;
                            break index;
                        }
                    }
                }
        return result;
    }

Answer 1

The problem is in the else part of. As you can’t conclude that the element in not in the inner array if just one comparison fails:

if(x==y) {
 result = true;  // ele present.
 break;
} else { 
 result = false; // can't conclude ele is absent..you might find it later.
 break index;
}

To fix this you might do:

public boolean linearIn(int[] outer, int[] inner) {

        for(int x: inner) {
                // assume x is absent.
                boolean result = false;
                for(int y: outer) {
                        // x found in outer.
                        if(x==y) {
                                // make result positive.
                                result = true;
                                // no need to look any further.
                                break;
                        }
                }
                // at this point not all elements of inner are 
                // tested for presence in outer. But one missing ele
                // would mean we return false.
                if(result == false) return false;
        }
        // all ele of inner are present in outer..return true.
        return true;
}