FirstLastPositionOfElement.java

package com.company;

import java.util.Arrays;

public class FirstLastPositionOfElement {

    public static void main(String[] args) {

        int[] nums = {5,7,7,8,8,10};
        int target = 8;

        System.out.println(Arrays.toString(searchRange(nums, target)));

    }

    static int[] searchRange(int[] nums, int target){
        int [] ans = {-1, 1};
        int start = search(nums, target, true);
        int end = search(nums, target, false);

        ans[0] = start;
        ans[1] = end;

        return ans;
    }

    static int search( int[] nums, int target, boolean findStartInd){
        int ans  =-1;
        //basic binary search
        int start = 0;
        int end = nums.length -1;

        while(start<= end){
            int mid = start + (end - start)/2 ;

            if(target > nums[mid]){
                start = mid + 1;
            } else if(target < nums[mid]){
                end = mid - 1;
            } else{
                ans = mid ;
                if(findStartInd){
                    end = mid - 1;
                } else{
                    start = mid + 1;
                }
            }
        }
        return ans;
    }
}