Index of first occurrence GFG

 package com.company;

public class FirstIndex {
    //    Index of first occurrence of an element
   public static int first(int[] arr, int x){
       int n = arr.length;
       for(int i = 0; i < n; i++){
           if(arr[i] == x){
               return i;
           }
       }
       return -1;
   }
   // efficient solution
    public static int firstOccur(int[] arr, int x, int low, int high) {
        int n = arr.length;
        int mid = (low + high) / 2;
        if (low > high) {
            return -1;
        }
        if(arr[mid] == x){
            if(mid == 0) {
                return mid;
            }
           else if(arr[mid - 1] == x){
                return firstOccur(arr, x, low, mid - 1);
            }
            else
                return mid;
        }
        else if(arr[mid] > x){
           return firstOccur(arr, x, low, mid - 1);
        }
        else{
           return firstOccur(arr,x, mid +1, high);
        }
    }
//Efficient solution iterative approach
    public static int find(int[] arr, int x) {
       int n = arr.length;
       int low = 0;
       int high = n - 1;
       while(low <= high){
           int mid = (low + high) / 2;
           if (arr[mid] == x) {
               if(mid == 0 || arr[mid - 1] != x) {
                   return mid;
               }
               else{
                   high = mid - 1;
               }
           }
           else if(arr[mid] > x){
               high = mid - 1;
           }
           else{
               low = mid + 1;
           }
       }
       return -1;
    }
    public static void main(String[] args) {
        int[] arr = {5,5,5};
        System.out.println(find(arr, 5));
    }
}