Array question - find first and last index of a number

Question is to find the first and the last index of any number in a sorted array. (repetition of numbers is allowed?

Below is my logic for that program. Can anyone tell me why it is showing TIME LIMIT EXCEEDED?
And if logic is incorrect then what is to be corrected.

import java.io.*;

import java.util.*;



public class Main{



public static void main(String[] args) throws Exception {

Scanner scn = new Scanner(System.in);

int n = scn.nextInt();

int a[] = new int[n];

for(int i=0;i<a.length;i++){

a[i] = scn.nextInt();

}

int l = 0;

int h = a.length - 1;

int x = scn.nextInt();

int first_index = 0;
int last_index = 0;
int mid = 0;

while(l <= h){

mid = (l+h)/2;

if( x < a[mid])
{

h = mid - 1;

}
else if(x > a[mid])
{

l = mid + 1;

}

else
{

first_index = mid;

last_index = mid;

}

}

int i = mid;

int j = mid;

if(a[first_index] == a[first_index-1]){

i--;

first_index--;

}

if(a[last_index] == a[last_index+1]){

j++;

last_index++;

}

first_index = i;

last_index = j;

System.out.println(first_index);

System.out.println(last_index);

}



}