I'm trying to perform a linear search on an array where it finds the last occurrence of a target. I'm stuck because my search is only finding the first occurrence of the target not the last.
/** Recursive linear search that finds last occurrence of a target in the array not the first
*
* @param items The array
* @param target the item being searched for
* @param cur current index
* @param currentLength The current length of the array
* @return The position of the last occurrence
*/
public static int lineSearchLast(Object[] items, Object target, int cur, int currentLength){
if(currentLength == items.length+1)
return -1;
else if (target.equals(items[cur])&& cur < currentLength)
return cur;
else
return lineSearchLast(items, target, cur +1, currentLength);
}
public static void main (String[] args){
Integer[] numbers5 = {1,2,4,4,4};
int myResult = lineSearchLast(numbers5, 4, 0, 5);
System.out.println(myResult);
You shouldn't need two index arguments - one (a current index) should do the trick. Moreover, to make sure that you find the last equivalent element first, it's prudent to start at the back and work forward.
/** Returns the index of the last occurance of target in items */
public static int findLastOccurance(Object[] items, Object target){
return findLastOccurance(items, target, items.length - 1);
}
/** Helper method for findLastOccurance(items, target). Recursively finds
* the index of the last occurance of target in items[0...cur]
*/
private static int findLastOccurance(Object[] items, Object target, int cur){
if(curr == -1) //We went past the start - missed it.
return -1;
else if (target.equals(items[cur])) //Found it
return cur;
else
return lineSearchLast(items, target, curr-1); //Work backwards
}