Linear seach finding the last index of a target within an array

Question

Write a method that when passed an array of integers arr, and an integer target, returns the last index at which target occurs in the array. Return -1 if the array is null or if target doesn’t exist in the array.

So I am using linear search to do this.

public static void linearSeach(int [] arr, target){
if( arr == null){
   return -1;
}
count = 0;
for (int i = 0; i< arr.length; i++){
    if( target == arr[i]){
       count ++;
}
}
// I cannot return both count and -1 so here is what I thought I should do
if( count >= 0){
return count;
}
else {
  return -1;
}}

Is this correct or the right approach?

No,it is asking for the last index

Scary Wombat
– Scary Wombat

2017-05-01 05:34:43 +00:00
Commented May 1, 2017 at 5:34 — Scary Wombat
– Scary Wombat, Commented May 1, 2017 at 5:34

Eran · Accepted Answer · 2017-05-01 05:33:38Z

1

No, you are returning the number of times the target number appears in the array. You should return the index of the last time it appears :

if (arr != null) {
    for (int i = arr.length - 1; i >= 0; i--){
        if (target == arr[i]) {
            return i;
        }
    }
}
return -1;

answered May 1, 2017 at 5:33

Eran

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Comments

Ashvin Gargav · Accepted Answer · 2017-05-01 06:19:40Z

0

public static void linearSeach(int [] arr, target){
    if( arr != null) {      
        int i = arr.length - 1
        while (i>=0){
            if( target == arr[i]){
                 return i;
            } 
            i= i-1              
        }
    }
    return -1;
}

answered May 1, 2017 at 6:19

Ashvin Gargav

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