Question

How to find first and last positions of an element in a sorted array in Java

Answer 1

public class MyClass {
    public static void find_first_and_Last_position(int arr[], int x) { 
        int len = arr.length; 
        int first = -1, last = -1; 
        
        for (int i = 0; i < len; i++) { 
            if (x != arr[i]) {
                continue; 
            }
            if (first == -1) {
                first = i; 
            }
            last = i; 
        } 
        if (first != -1){ 
            System.out.println("First positions = " + first + " Last positions = " + last); 
        } 
        else
            System.out.println("Not Found"); 
    } 
    public static void main(String args[]) {
        int arr[] = {1, 3, 7, 8, 3, 1, 9}; 
        int n = 3; 
         
        find_first_and_Last_position(arr, n); 
    }
}



/*
run:

First positions = 1 Last positions = 4

*/

 

70+ SQL courses for beginners and professionals

Answer 2

public class MyClass {
    public static int[] find_first_and_Last_position(int arr[], int x) { 
        int len = arr.length; 
        int first = -1, last = -1; 
        
        for (int i = 0; i < len; i++) { 
            if (x != arr[i]) {
                continue; 
            }
            if (first == -1) {
                first = i; 
            }
            last = i; 
        } 
        
        int[] result = new int[2]; 
        result[0] = first; 
        result[1] = last; 
          
        return result; 
    } 
    public static void main(String args[]) {
        int arr[] = {1, 3, 7, 8, 3, 1, 9}; 
        int n = 3; 
         
        int[] result =  find_first_and_Last_position(arr, n); 
         
        if (result[0] != -1){ 
            System.out.println("First positions = " + result[0] + " Last positions = " + result[1]); 
        } 
        else
            System.out.println("Not Found"); 
    }
}



/*
run:

First positions = 1 Last positions = 4

*/

 

70+ SQL courses for beginners and professionals