A different approach using hash table

    public static int introTutorial(int V, List<Integer> arr) {
        int[] hash = new int[2001];
        for(int i=0;i<arr.size();i++) 
            hash[arr.get(i)+1000] = i; // 1000 is because we have negative numbers too... :)
        return hash[V+1000];
    }

Rust Solution:

fn introTutorial(V: i32, arr: &[i32]) -> i32 {
    let index = arr.iter().position(|&x| x == V).unwrap();
    return index as i32;
}

binary search. O(log n)

 `    int leftMarker = 0;
    int rightMarker = arr.size() - 1;
    do {
        int pivot = (leftMarker + rightMarker) / 2;
        if (arr.get(pivot) == V) return pivot;
        if (arr.get(pivot) > V) rightMarker = pivot - 1;
        else leftMarker = pivot + 1;
    } while (leftMarker <= rightMarker);`

JavaScript: function introTutorial(V, arr) { // Write your code here return arr.indexOf(V); }

JAVA

public static int introTutorial(int V, List<Integer> arr) {
// Write your code here
int result=0;
    for(int i=0;i<arr.size();i++){
       if(V==arr.get(i)){
           result=i;
           break;
       }
    }

    return result;
}

}