CODEWITHSUNDEEP
javaarraysarraylist
byerlyfactor
byerlyfactor

Reputation: 3

Check to see if an array is contained within another array

The problem is: Check to see if the array arr2 is contained within the arr1 in the same order. The arr2 could be contained anywhere with in arr1.

public boolean contains(String[] arr1, String[] arr2)
{
   int length  = 0;
   if(arr2.length > arr1.length)
      return false;
   for(int i = 0; i < arr2.length; i++)
   {
      if(arr2[i] == arr1[i])
          length++;
   }
   if(length == arr2.length)
      return true;
   else
      return false;
}

TESTER: contains({"1", "2", "3"}, {"1", "2"}) → true

RUN: TRUE

TESTER: contains({"1", "2", "3"}, {"2", "3"}) → true

RUN: FALSE

TESTER: contains({"1", "2", "3"}, {"2", "1"}) → false

RUN: TRUE

TESTER: contains({"MARY", "A", "LITTLE", "LAMB"}, {"A", "LITTLE", "LAMB"}) → true

RUN: FALSE

TESTER: contains({"MARY", "A", "LITTLE", "LAMB"}, {"MARY", "A", "LITTLE", "LAMB"}) → true

RUN: TRUE

.

I don't know where I'm going wrong. Thanks for help.

Upvotes: 0

Views: 288

Answers (2)

iameven
iameven

Reputation: 348

  • use arr[1].equals(arr[2]) instead arr[1] == arr[2]
  • should judge in the loop not before loop

I modify the code like it:

public static boolean contains(String[] arr1, String[] arr2) {
    int length = 0;

    for (int i = 0; i < arr1.length; i++) {
        if (arr2[length].equals(arr1[i])) {
            length++;
        } else {
            length = 0;
        }
        if (length == arr2.length)
            return true;
    }
    return false;
}

Upvotes: 1

Scott Hunter
Scott Hunter

Reputation: 49803

You are only comparing both arrays from the beginning; you need to also consider the cases when you start comparing at a different location in arr1. For example, you would get TRUE in the second example if you started comparing at the second element of arr1 (same for the fourth example).

Upvotes: 0

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