To begin, I am doing this using solely arrays - meaning no hash maps or array lists. It is in Java.
I am trying to create a method, project, which takes in two integer arrays (of different sizes).
I am trying to compare them in a way to get the following output: Projecting [1, 3, 5, 3] to [2, 1, 6, 3, 1, 4, 5, 3] results in: [1, 3, 1, 5, 3]. However, Projecting [2, 1, 6, 3, 1, 4, 5, 3] to [1, 3, 5, 3] results in: [1, 3, 5, 3].
I believe the nested for loop might be wrong as it is iterating through the first indices for the first array all the way through the second array, then going to the next.
I'm getting an ArrayIndexOutOfBoundsException for the line that is starred (tempArray[i] == arr1[i], I know it shouldn't be tempArray[i] but not sure what exactly to put. I'm not sure how to compare them in a way to produce the line above, as it needs to be in order. What would be the best way to accomplish this or correct the code?
I attempted the following code:
public int[] project(int[] arr1, int[] arr2) {
int counter = 0;
for(int i=0 ; i < arr1.length; i++) {
for (int j=0; j < arr2.length; j++) {
if(arr1[i] == arr2[j]) {
counter++;
}
}
}
int[] tempArray = new int[counter];
for(int i=0 ; i < arr1.length; i++) {
for (int j=0; j < arr2.length; j++) {
if(arr1[i] == arr2[j]) {
**tempArray[i] = arr1[i];**
}
}
}
Edit: The ArrayIndexOutOfBounds error is gone, but now my return statement is: Projecting [1, 3, 5] to [2, 1, 6, 3, 1, 4, 5, 3] results in: [1, 3, 5, 0, 0], when it needs to be Projecting [1, 3, 5] to [2, 1, 6, 3, 1, 4, 5, 3] results in: [1, 3, 1, 5, 3]. Any idea what is causing this issue?
I think you have a typo in your first for loop
change this to later
arr1[i] == arr2[i]
to
arr1[i] == arr2[j]
Regarding overlapping issues in the projection array, you need to maintain different value as your index rather than i or j which is used by arr1 and arr2 respectively
int[] tempArray = new int[counter];
int index = 0;
for(int i=0 ; i < arr1.length; i++) {
for (int j=0; j < arr2.length; j++) {
if(arr1[i] == arr2[j]) {
tempArray[index++] = arr1[i];
}
}
}
For the values which you are expecting you should loop through arr2 first
for(int j=0 ; j < arr2.length; j++) {
for (int i=0; i < arr1.length; i++) {
if(arr1[i] == arr2[j]) {
tempArray[index++] = arr1[i];
}
}
}
If the contents of array are not hardcoded and you dont know the order in which you want to pass, you can make use of length
int[] ans;
if(a.length < b.length) {
ans = project(a, b);
} else {
ans = project(b, a);
}
Output:
[1, 3, 1, 5, 3]
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